Wast heat recovery

Biogas potential was explored for animal manure, wheat straw, food waste and rice straw. Batch experiments were performed at a laboratory scale using potential biomethane assays (BMP) for a period of 50 days. The biogas yield was observed higher when using rice straw (0.40 m3/kg VSadded) as a substrate, as compared to wheat straw (0.33 m3/kg VSadded) and animal manure (0.30 m3/kg VSadded) substrates. Around 10% of biogas was produced in the initial phase of 4 days for manure, wheat straw, and rice straw feedstocks. During the middle phase of 30 days for these feedstocks, 65 – 80% of biogas was produced. Less than 20% of biogas was produced during the final phase of last 16 days of the experiment. The biogas production from food waste was found lowest (0.02 m3/kg VSadded) among all substrates. Therefore, the anaerobic digestion (AD) of both food waste and animal manure is more suited in co-digestion fashion than mono-digestion.

Humidification dehumidification (HDH) desalination system is a thermal-based desalination technology that is suitable for small-scale water desalination applications. In this paper, we present an experimental and ther-modynamic analysis of the energetic performance of two HDH cycles. The HDH cycles considered are the basic open-air open-water (OAOW) cycle and the modified closed-water open-air (CWOA) cycle with the options of brine recirculation. An experimental investigation is performed on the modified cycle to validate the theoretical model that is used to assess the energetic performance of both the basic and modified cycles. The theoretical model is found to be in a good agreement with the experimental data with a maximum percentage deviation of 5% from the experimental data. Furthermore, limiting cases of the system are explored. Within the limiting cases, the modified cycle recorded about 100% improvement in the energy performance over the basic cycle due to heat recovery process associated with the modified cycle. Additionally, a cost analysis was performed to determine the cost of freshwater production by the presented desalination cycles. Results show that the freshwater price varied from 4.10 to 6.55 $/m 3 and 0.79 to 2.25 $/m 3 for the basic OAOW HDH cycle and the modified CWOA HDH cycle, respectively.

Enerji verimliliği, binalarda yaşam standardı ve hizmet kalitesinin, endüstriyel işletmelerde ise üretim kalitesi ve miktarının düşüşüne yol açmadan, birim hizmet veya ürün miktarı başına enerji tüketiminin azaltılmasıdır. Bu tanımdan yola çıkılarak Dünya ve Türkiye'de enerji verimliliği adına birçok araştırma yapılmaktadır. Bu çalışmada, enerji verimliliği uygulamaları üzerinde durulmuş ve Konya'da uygulanan enerji verimliliği çalışmalarından bahsedilmiştir. Bunlar; binalarda gerçekleştirilen verimlilik uygulamaları, Konya Sanayi'sindeki uygulamalar, kojenerasyon sistemleri ve çalışma prensipleri, endüstriyel yalıtım ve kazanlardaki verimlilik uygulamaları ve Konya Büyükşehir Belediyesi tarafından yürütülen katı atık dönüşüm uygulamalarıdır. Anahtar Kelimeler: Enerji verimliliği, ısı geri kazanımı, kojenerasyon, Konya, yalıtım. GİRİŞ 2010 yılı verilerine göre, dünya üzerinde mevcut kanıtlanmış petrol rezervlerinin 46, doğal gaz rezervlerinin 63, kömür rezervlerinin de yaklaşık olarak 400 yıllık ömre sahip olduğu tahmin edilmektedir. En önemli enerji kaynakları olan petrol ve kömür gibi fosil kaynaklı yakıtların hızla tükeniyor olması, enerji üretim ve tüketim süreçlerinde ortaya çıkan sera gazı emisyonlarının küresel ısınma ve iklim değişikliğine neden olması, ülkemizin enerji kaynakları kullanımında %70 oranında ihracata bağımlı olması enerji verimliliğinin önemini artırmıştır. Sanayide enerji verimliliği ise daha geniş bir biçimde şu şekilde tanımlanır; gaz, buhar, ısı, hava, elektrik vb. enerji kayıplarını önlemek, çeşitli atıkların geri kazanımını ve değerlendirilmesini sağlamak veya ileri teknoloji ile üretimi düşürmeden enerji talebini azaltmak, daha verimli enerji kaynakları, gelişmiş endüstriyel süreçler, enerji geri kazanımları gibi etkinliği artırıcı önlemlerde bulunmaktır [1].Sanayi tesislerinde kullanılabilen verimlilik uygulamalarına

Vehicles could save ~110 million gallons of gasoline per year in the U.S. with heat exchangers acting as heat recovery ventilators in the air conditioning systems. Even more energy could be saved with in-vehicle heat exchangers by reducing heating energy in plug-in vehicles. Currently, vehicles do not have heat recovery ventilators because of the high cost of conventional metal heat exchangers. To overcome this challenge, low-cost expanded polymer microchannel heat exchangers were studied. Forward conduction laser welding was used to join 25-micron thick linear low-density polyethylene sheets, which were then fixed into shape and expanded. The microchannel polymer heat exchangers were tested at various air flow rates. At the maximum flow rate, the effectiveness was ~70% and the implications of this expanded heat exchanger in other applications are discussed.

In the present study, the effect of triangular, rectangular and trapezoidal ribs on the laminar heat transfer of water-Ag nanofluid in a ribbed triangular channel under a constant heat flux was numerically studied using finite volume method. Height and width of ribs have been assumed to be fixed in order to study the effect of different rib forms. Modeling were performed for laminar flow (Re=1, 50 and 100) and nanofluid volume fractions of 0, 2% and 4%. The results indicated that an increase in volume fraction of solid nanoparticle leads to convectional heat transfer coefficient enhancement of the cooling fluid, whereas increasing the Nusselt number results in a loss of friction coefficient and pressure. Also, along with the fluid velocity increment, there will be an optimal proportion between heat and hydrodynamic transfer behavior which optimizes performance evaluation criteria (PEC) behavior. Among all of the investigated rib forms, the rectangular one made the most changes in the streamlines and the triangular form has the best thermal performance evaluation criteria values. For all studied Reynold numbers, heat transfer values are least for rectangular rib from. Therefore, trapezoidal ribs are recommended in high Reynold numbers.

A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger (HX). Thus, this study focuses on cost optimization of HX designs for flow-through SWPs using high-effectiveness polymer microchannel HXs. The theoretical foundation for the cost optimization of a polymer microchannel HX is provided, and outputs are plotted in order to provide guidelines for designers to perform HX optimizations. These plots are used in two case studies: (1) substitution of a coiled copper HX with polymer microchannel HX, and (2) design of a polymer microchannel HX for a 3-D printed collector that can fit in an arbitrary build volume. The results show that substitution of the polymer expanded HX reduced the overall expenditure for the system by a factor 50, which aids in making the system more economical. For the second case study, the results show how future system designers can optimize an HX for an arbitrary SWP geometry. The approach of distributed manufacturing using laser welding appears promising for HX for SWP.

In this study, exergo-economic analysis of two layouts of humidification-dehumidification (HDH) desalination systems driven by a vapor compression heat pump (HP) is presented and discussed. The systems are closed-air open-water water-heated cycle coupled with a heat pump (HP-HDH-WH), and modified air-heated cycles integrated with a heat pump (HP-HDH-AH). For the purpose of comparison, a conventional closed-air open-water (CAOW) electric water heated HDH system (E-HDH-WH) is also presented. Exergy destruction, exergetic efficiency and product cost are evaluated for these systems. The influence of input parameters such as mass flowrate ratio, dehumidifier effectiveness, compressor isentropic efficiency, and feed water temperature on second-law efficiency and exergy destruction associated with the major components of the systems are analyzed. The impact of input cost parameters is investigated using two different approaches. The analysis shows that evaporator and compressor are the components with the largest exergy destruction. The exergy efficiency for the HP-HDH air-heated unit, HP-HDH water-heated unit, and E-HDH water-heated unit is found to be 1.097%, 0.06965% and 0.05795%, respectively. The cost of desalinated water evaluated by current analysis for HP-HDH air-heated system, HP-HDH water-heated cycle, and E-HDH water-heated unit is found to vary from 4.61$/m 3 to 5.49$/m 3 , 6.00$/m 3 to 7.14$/m 3 , and 4.44$/m 3 to 14.95$/m 3 , respectively. The results generally reveal that HP-HDH air-heated cycle shows better performance both from energetic and exergetic viewpoints.

Energy efficiency is more and more a crucial matter in the agenda of energy intensive industries: it constitutes a source of competitive advantage, indicator to social responsibility and environmental awareness. Among the various solutions available, the Organic Rankine Cycle (ORC) turbo-generators address to this topic by turning the waste heat sources into electrical power.
Thanks to the peculiarities of the ORC technology, these turbo-generators present key advantages such as long-life, very few maintenance and operation activities required, high availability, automatic and high-efficient operation at partial loads; for all these reasons ORC turbo-generators are more and more the preferred solution to waste-heat recovery projects in energy-intensive processes such as iron & steel, glass, waste incinerator, refineries and cement industries.

To meet the demand for energy demand reduction in heating, ventilation and air-conditioning systems, a novel design incorporating a heat recovery device into a wind tower was proposed. The integrated system uses a rotary thermal wheel for heat recovery at the base of the wind tower. A 1:10 scale prototype of the system was created and tested experimentally in a closed-loop subsonic wind tunnel to validate the Computational Fluid Dynamics (CFD) investigation. Wind towers have been shown to be capable of providing adequate ventilation in line with British Standards and the Chartered Institution of Building Services Engineers (CIBSE) guidelines. Despite the blockage of the rotary thermal wheel, ventilation rates were above recommendations. In a classroom with an occupancy density of 1.8 m2/person, the wind tower with rotary thermal wheel was experimentally shown to provide 9 L/s per person at an inlet air velocity of 3 m/s, 1 L/s per person higher than recommended ventilation rates. This is possible with a pressure drop across the heat exchanger of 4.33 Pa. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature 2 °C, this passive recovery has the potential to reduce demand on space heating systems.

A performance study was conducted on the combined cycle power plant (CCPP), which is one of the most important options for replacement and repowering of the available steam power plant. The thermodynamic performance of these plants depends on the ambient temperature which varies considerably from one season to another. The objective of the current work is to investigate the effects of these variations on the performance of combined cycle power plants. In this study AL-Mussaib thermal power plant has been chosen for repowering, for this purpose, AL-Khairat gas turbines are used and the effect of duct burner is investigated. The repowered combined cycle power plant (RCCPP) consists of four gas turbines and four heat recovery steam generator (HRSG) with one steam turbine was associated with the unit in this model. The theoretical analysis was made according to both first and second laws of thermodynamic analysis. A generalized computer program was prepared by Fortran 90 for this purpose. It is found that the net power output, thermal and exergy efficiencies of the RCCPP increases as the ambient temperature decreases. The mass flow rate of steam decreases with the increase of ambient temperature at constant compressor pressure ratio and turbine inlet temperature (TIT). The exergy destruction in the combustion chamber and HRSG decreases while, the exergy destruction of the condenser increases greatly as the ambient temperature increases

This paper focuses on the key problem of future aeronautics: which relates on energy efficiency and environmental footprint on a scientific point of view. Reducing emissions and increasing the energy efficiency would be both a key element to propel the market and increase the diffusion of personal aerial transport against ground transportation. Novel vehicle concepts and systems will be necessary to propel this innovation which could revolutionize our way of moving. This paper approaches an energetic preliminary design of a vehicle concept which could fulfill this social and cultural objective. Low cost energy efficient vehicles, which could be suitable for personal use with a high economic efficiency and without needs of airports, seem actually a real dream. Otherwise, is it a feasible goal or a scientific dream? Otherwise, a design method based on first and second law and thermodynamic and constructal law could allow reaching those goals. This paper presents a preliminary design of a propulsion concept which could have the ambition and demonstrate the theoretical feasibility, using mostly existing industrial components and indicating the few ones which are not disposable today, but giving preliminary guidelines for their development.

Solid−liquid phase change materials (PCMs) are attractive candidates for thermal energy storage and electronics 8 cooling applications but have limited applicability in state-of-the-art technologies due to their low intrinsic thermal conductivities. 9 Recent efforts to incorporate graphene and multilayer graphene into PCMs have led to the development of thermal energy 10 A dx.doi.org/10.1021/am502819q | ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX cdz00 | ACSJCA | JCA10.0.1465/W Unicode | research.3f (R3.6.i5 HF01:4227 | 2.0 alpha 39) 2014/03/19 08:04:00 | PROD-JCAVA | rq_3699599 | 7/07/2014 13:44:53 | 9 | JCA-DEFAULT 47 natural convection (i. e., buoyant fluid movement) within the 48 PCM during the melt phase and therefore reduce the rate of 49 melt front propagation. Consequently, researchers have turned 50 their attention to high thermal conductivity, carbon-based 51 nanoparticles (such as CNTs and graphene) as filler materials. 52 This is primarily due to recent work that reports record-high 53 intrinsic thermal conductivities for carbon-based nanoparticles 54 (up to 6000 W/mK). 11,12 Using a standard mixing approx-55 imation for materials having continuous, percolating fillers (eq 56 1), 13 one can calculate an expected thermal conductivity of a 57 PCM embedded with carbon nanoparticles.

The objective of this experiment is to study the function and the working of shell and tube heat exchanger. Calculations on the heat transfer and heat loss were carried out for energy balance study. LMTD and heat transfer coefficient also calculated for this experiment. From the data collected, we found out that configuration of Shell and Tube heat exchanger has a higher effectiveness than the co-current flow

Increase in the speed of processors has led to crucial role of communication in the performance of systems. As a result, routing is taken into consideration as one of the most important subjects of the Network on Chip architecture. Routing algorithms to deadlock avoidance prevent packets route completely based on network traffic condition by means of restricting the route of packets. This action leads to less performance especially in non-uniform traffic patterns. On the other hand True Fully Adoptive Routing algorithm provides routing of packets completely based on traffic condition. However, deadlock detection and recovery mechanisms are needed to handle deadlocks. Use of global bus beside NoC as a parallel supportive environment, provide platform to offer advantages of both features of bus and NoC. This bus is useful for broadcast and multicast operations, sending delay sensitive signals, system management and other services. In this research, we use this bus as an escaping path for deadlock recovery technique. According to simulation results, this bus is suitable platform for deadlock recovery technique.

Applying a thin, protective coating of a nontoxic, chemically resistant epoxy to the interior of existing pipes is an alternative method to pipe replacement. In order to find the controlling parameters in this method, in this study, viscous epoxy was propelled by compressed air through clear polyvinyl chloride (PVC) pipes. Epoxy flow was annular, and it hardened to form a thin, uniform coating on the inner pipe surface. A video camera was employed to record fluid motion, and the thickness of the coating was measured using an image analysis program named ImagJ. Tests were done with varying air temperature, airflow rate, piping configuration, and epoxy temperature. A one-dimensional numerical algorithm was developed to model fluid flow, heat transfer, and epoxy curing. Heating the epoxy makes it move faster because liquid viscosity decreases with increasing temperature. The coating was significantly thicker at the bottom of a horizontal pipe than at the top due to sagging of the epoxy coating after it had been applied, resulting in flow from the top to the bottom of the pipe. Sagging could be reduced by maintaining airflow until curing was almost complete and the epoxy had hardened enough to prevent it from moving easily. The combination of the experimental results and numerical modeling showed that the most important parameters controlling the speed of the epoxy and coating thickness were the air flow rate and temperature, since they determine the shear forces on the epoxy layer and the rate at which the epoxy cures. Raising air temperature increases the reaction rate and therefore decreases the time required for the epoxy to cure inside the pipe. The results of the simulation showed a very good agreement with the experimental results in pipes with 1-in diameter or less.

This work is an in-depth analysis of the performance behavior of a small scale single effect thermal desalination plant. The  prototype, which refers to the distributed micro cogeneration field, consists of a 1 kWe Stirling engine coupled with a single  effect thermal desalination plant for the simultaneous production of electricity and >150 L/day of fresh water.
The prototype was able to work in two different operation modes: batch operation and continuous operation. In the former, the evaporator tank is initially filled with the salt water up to its maximum and the evaporation process ends as the salt water level reaches the top of the coil. In the latter, concentrate is continuously extracted and salt water is fed inside the evaporator tank in order to maintain brine salinity almost constant.
In a previous work authors investigated the plant performance in batch operation mode finding a good agreement with the predicted results. In this work, plant performance is evaluated in continuous operation and compared to the batch operation mode. In both cases, fresh water production reached a maximum of about 7 L/h in the best operating conditions. However, despite the higher complexity of the plant, performance is worse in the continuous operation mode due to the negative effect of the continuous seawater flow. Indeed, the lower the salt content of the treated water, the lower the fresh water production due to process limits which will be extensively discussed in the paper. More precisely, the plant’s average productivities were about 1.3 L/kWh and 1.16 L/kWh of thermal energy input in batch and continuous operation modes respectively.
In any case, the apparatus exhibited a very good response to varying thermal power input thus confirming the opportunity to feed the desalination plant also with different forms of waste heat.
Hence the proposed solution, studied for a coupling with a 1 kWe Stirling engine, can be easily applied also to the other micro-CHP technologies.

Channels not receiving the same amount of flow (flow maldistribution) is an important effectiveness loss for high effectiveness heat exchangers. This paper develops a finite difference model of a counter flow heat exchanger. For modeled scenarios very good agreement with previous studies and analytical calculations was achieved. For independent pairs of hot and cold channels, as flow rate is reduced, the effectiveness asymptotically approaches the irregularity parameter (a measure of channel flow maldistribution). With thermal coupling between pairs of channels (measured by an equivalent Peclet number), effectiveness continues to increase with decreasing flow rate. These results hold for uncorrelated flow maldistribution on both sides or no flow maldistribution on one side. However, when flow maldistribution is positively correlated, effectiveness is higher; and, when it is negatively correlated, effectiveness is lower. A number of resulting graphs illustrate the effectiveness for each channel with different flow rate and correlation. While one exemplary application is a polymer expanded microchannel heat exchanger, the model could be used for other heat exchangers.

Heat transfer coefficient for cooling tower is determined experimentally and theoretically, the latent heat
and air flow heat to  are  calculated.  Thickness of heat layer is calculated and is  then  compared to theoretically
calculated the displacement layer. The heat transfer coefficient is calculated based on the values of displacement
layer and its deviation from theoretically calculated one is up to 3 times in the range of air velocity of 1.3-3.0 m/s.
The difference in temperature of the air and water film is calculated.

Heat and fluid flow in a rectangular channel heat sink equipped with longitudinal vortex generators have been numerically investigated in the range of Reynolds numbers between 25 and 200. Aqueous solutions of carboxymethyl cellulose (CMC) with different concentrations (200–2000 ppm), which are shear-thinning non-Newtonian liquids, have been utilised as working fluid. Three-dimensional simulations have been performed on a plain channel and a channel with five pairs of vortex generators. The channels have a hydraulic diameter of 8 mm and are heated by constant wall temperature. The vortex generators have been mounted at different angles of attack and locations inside the channel. The shear-thinning liquid flow in rectangular channels with longitudinal vortex generators are described and the mechanisms of heat transfer enhancement are discussed. The results demonstrate a heat transfer enhancement of 39–188% using CMC aqueous solutions in rectangular channels with LVGs with respect to a Newtonian liquid flow (i.e. water). Additionally, it is shown that equipping rectangular channels with LVGs results in an enhancement of 24–135% in heat transfer performance vis-à-vis plain channel. However, this heat transfer enhancement is associated with larger pressure losses. For the range of parameters studied in this paper, increasing the CMC concentration, the angle of attack of vortex generators and their lateral distances leads to an increase in heat transfer performance. Additionally, heat transfer performance of rectangular channels with longitudinal vortex generators enhances with increasing the Reynolds number in the laminar flow regime.

The paper presents a theoretical analysis of three advanced gas turbine recuperative-cycles, that is the intercooled, the reheat, and the intercooled and reheat cycles. The internal irreversibilities, which characterise the compression and expansion processes, are taken into account through the polytropic efficiencies of the compressors and turbines. As customary in simplified analytical approaches, the study is carried out for an uncooled closed-circuit gas turbine without pressure losses in the heat exchangers and using a calorically perfect gas as working fluid. Although the accurate performance prediction of a real gas turbine is prevented by these simplifying assumptions, this analysis provides a fast and simple approach which can be used to theoretically explain the main features of the three advanced cycles and to compare them highlighting pros and contra. The effect of the heat recuperation is investigated comparing the thermal efficiency of a given cycle type with those of two reference cycles, namely the non-recuperative version of the analysed cycle and the simple cycle. As a result, the ranges of the intermediate pressure ratios returning a benefit in the thermal efficiency in comparison with the two reference cycles have been obtained for the first time. Finally, for the sole intercooled and reheat recuperative-cycle, a novel analytical expression for the intermediate pressure ratios yielding the maximum thermal efficiency is also given.

This paper presents a new design methodology of cross flow ventilated heat sinks. An accurate design of both finned and circular pin system with inline configuration has been produced. The model is based on the well tested experimental lumped parameter analysis of cross-flow heat exchangers by Gnielinski. The presented method is intended to support the design of heat sinks with well defined performances of cross flow ventilated heat sinks. An evaluation of the physical properties of the sink is performed and different cases are calculated. They allow comparing the performance in terms of both geometrical parameters of the exchanger and air speed. An effective model of the equations is produced and on this basis a multi-objective optimization is performed.

in this study, ethylene furnace modeling is carried out by ethane pyrolysis (thermal cracking or hydrocracking)
method in Arya Sasol Petrochemical Company (ninth olefin unit, Assaluyeh, Iran), which includes the solution
of kinetic equations and transfer phenomena, by the forward finite difference method in the MATLAB. Due to
study and compare coke formation, a specific time period has been selected in equal segments and equations
have been solved. It means that in a length segment of coil (Δz), momentum, energy as well as mass equations
are solved, then the amount of precipitated coke in each length segment is achieved. With new efficient coil
diameter calculating all mentioned approach will be repeated for next time segment. The results of this model
have been compared with actual data and deviation has been reported. It was found that modeling approach is
more capable to define the parameters of coke formation equations. The model has a good agreement between
the values of prediction and experimental of in most cases.

Shopping centers offer services and produce goods, an outcome which requires use of energy as an input. Energy efficiency and conservation measures can be adopted to reduce the energy cost component of operational costs in such centers. In this paper, tips about saving of energy in shopping centers have been shared. The back of the hand approaches to conserving energy can be adopted by people who are not professionals in energy efficiency.

This paper presents results on the evaluation of energy utilisation efficiency and economic and environmental performance of a micro-gas turbine (MGT) based trigeneration system for supermarket applications. A spreadsheet energy model has been developed for the analysis of trigeneration systems and a 2,800 m 2 sales area supermarket was selected for the feasibility study. Historical energy demand data were used for the analysis, which considered factors such as the fraction of the heat output used to drive the absorption chillers, the chiller COP and the difference between electricity and gas prices. The results showed that energy and environmental benefits can be obtained from the application of trigeneration systems to supermarkets compared to conventional systems. The payback period of natural gas driven trigeneration systems and greenhouse gas emissions savings will depend on the relative gas and electricity prices and the COP of the vapour compression and absorption systems. It was also shown that operation at full electrical output gives a better performance than a heat 2 load-following strategy due to the reduction of the electrical generation efficiency of the MGT unit at part load conditions.

The discharge temperature of CO2 transcritical system can provide high grade heat that can be reclaim and re-use for hot water services, space heating and cooling systems. This paper investigates the performance of an innovative booster R-744 system with heat recovery at different operating conditions based on its mathematical EES model which includes the variation of the cooling capacities of different size of stores, discharge pressures, receiver pressure and superheats.

1
Trigeneration in food retail: an energetic, economic and environmental
evaluation for a supermarket application
N. Sugiartha,*, S.A. Tassou , I. Chaer1, , D. Marriott2
School of Engineering and Design, Brunel University, Uxbridge, Middlesex, UB8 3PH, UK
1Department of Engineering Systems, London South Bank University, 103 Borough Road, SE1 0AA, UK
2 Doug Marriott Associates, Kent, UK
Abstract
This paper presents results on the evaluation of energy utilisation efficiency and
economic and environmental performance of a micro-gas turbine (MGT) based
trigeneration system for supermarket applications. A spreadsheet energy model has been
developed for the analysis of trigeneration systems and a 2,800 m2 sales area
supermarket was selected for the feasibility study. Historical energy demand data were
used for the analysis, which considered factors such as the fraction of the heat output
used to drive the absorption chillers, the chiller COP and the difference between
electricity and gas prices. The results showed that energy and environmental benefits
can be obtained from the application of trigeneration systems to supermarkets compared
to conventional systems. The payback period of natural gas driven trigeneration systems
and greenhouse gas emissions savings will depend on the relative gas and electricity
prices and the COP of the vapour compression and absorption systems. It was also
shown that operation at full electrical output gives a better performance than a heat load-following strategy due to the reduction of the electrical generation efficiency of the
MGT unit at part load conditions.

Near-net pyramidal shaped fin arrays have been produced using the Cold Gas Dynamic Spraying (CGDS)
process. Some fin arrays have been modified to trapezoid prism geometry by grinding the top of the pyramidal
fins to study the effect of varying the base angle, at a constant fin height. All fin arrays have been
tested for thermal and hydrodynamic performance. Little variation in thermal conductance between
ground and as-sprayed fins is observed for the same fin heights, while a slightly more significant variation
in pressure loss through the fin array is found. A comparison of these performances was performed with
plain rectangular fins. The new fin geometry outperforms the traditional rectangular fins when comparing
the thermal conductance per unit pumping power for a given heat exchanger volume over the range
of Reynolds numbers studied.

Three stage standalone solar thermal Multi Effect Desalination (MED) pilot plant for remote and arid rural regions of Sultanate of Oman using fixed focus type Scheffler concentrator producing 100 litres per day has been set up at author's institute. Preliminary tests carried out on this plant yielded lower outputs of 60-65 litres per day. Heat loss through high temperature brine discharged at 85 o C was observed as one of the reasons for lower yield. Literature reviewed and analysis shown that desalination outputs can be increased with increased feed water inlet temperature. To recover this heat and preheat the feed water supplied, brine heat recovery unit using counter flow type shell and coil heat exchanger has been proposed in this paper. Helically coiled heat exchanger has been selected for its compactness, higher heat transfer area per unit volume, higher inside heat transfer coefficient and lower fouling rates due to induced turbulence. The operating parameters of this heat exchanger will handle hot brine at 80-85 o C and 1 bar pressure. In the present work, heat load, number of turns, coil length and pressure drop calculations are done for estimating the theoretical values based on heat transfer & fluid mechanics principles using numerical correlations from the literature reviewed. The steady state analysis has shown that that coil pitch,inside tube diameter, mass flow rate through the coil and shell affects the heat transfer rates. Practical dimensional constraints have been taken into consideration while finalising the dimensions of the heat exchanger. Overall effectiveness of 84.6% has been calculated for the proposed heat exchanger.

Turbo compounding is one of the ways to recover wasted energy in the exhaust. This paper presents the effectiveness of series and parallel turbo compounding on a turbocharged diesel engine. A power turbine is coupled to the exhaust manifold, either in series or in parallel with the turbocharger, to recover waste heat energy. The effectiveness and working range of both configurations are presented in this paper. The engine in the current study is a 6 cylinder, 13 L diesel engine. Both the configurations were modeled with one dimensional simulation software. The current study found that series and parallel turbo compounding could improve average brake specific fuel consumption (BSFC) by 1.9% and 2.5%, respectively. When the power turbine is mechanically connected to the engine, it could increase the average engine power by 1.2% for the series configuration and 2.5% for the parallel configuration.

This article presents experimental and theoretical investigations of a new configuration of an open-air open-water (OAOW), water-heated (WH), humidification-dehumidification (HDH) desalination system coupled with a vapor compression heat pump (HP) that considers two possibilities of energy recovery. Three different HDH system configurations including the basic system HDH-HP (without brine energy recovery), system A (basic system with brine energy recovery for pre-heating saline water), and system B (basic system with brine energy recovery for pre-heating ambient air) are presented. The performance of the basic system is examined experimentally; while that of systems A and B are assessed theoretically. Furthermore, the theoretical analysis is extended to the basis system to address the boundaries, constraints and limitations of experimental equipment, by analyzing the system performance at extended operation conditions. Results reveal that the developed model shows a good agreement against the experimental findings. Results also show that systems A and B portrayed superior performance over the basic system (especially system A), due to the energy recovery from the rejected brine. A maximum GOR of 2.72, RR of 2.56%, water productivity of 9.23 kg/h and a minimum freshwater cost of 15.14$/m3 are attained experimentally, while theoretical results for system A revealed a maximum GOR of 5.06, RR of 3.98%, water productivity of 11.46 kg/h, and a minimum price of freshwater of 12.38$/m3.

With the shift to a service based society, providing opportunities for outdoor recreation that enables mental and physiological self-regulation has become an increasingly important landscape function. Recent research has provided considerable evidence that visits to near-natural everyday landscapes promote psychological and physical health. However, little is so far known about the effects of people's regular outdoor recreation in their local natural environment on their well-being and, in particular, on their psychological resilience. In our project we address this research gap by investigating nearby outdoor recreation behaviour in three urbanized regions in Switzerland, each of which has a different predominant culture and language (German, French and Italian speaking). A standardized questionnaire was sent to a random sample of residents (N¼ 1200) in each region. Stepwise regression supported the hypothesis that regular nearby outdoor recreation has a significant but rather marginal effect on respondents' reported well-being and their psychological resilience, even when systematically controlled. However, similar effect sizes, in particular in terms of psychological resilience, were found with other leisure activities. More generally, we found that well-being and psychological resilience were influenced by different factors, and that increasing psychological resilience mainly required a long duration of recreation or leisure activities.

A finite difference model of a heat exchanger (HX) considered maldistribution, axial conduction, heat leak, and the edge effect, all of which are needed to model a high effectiveness HX. An HX prototype was developed, and channel height data were obtained using a computerized tomography (CT) scan from previous work along with experimental results. This study used the core geometry data to model results with the finite difference model, and compared the modeled and experimental results to help improve the expanded microchannel HX (EMHX) prototype design. The root mean square (RMS) error was 3.8%. Manifold geometries were not put into the model because the data were not available, so impacts of the manifold were investigated by varying the temperature conditions at the inlet and exit of the core. Previous studies have not considered the influence of heat transfer in the manifold on the HX effectiveness when maldistribution is present. With no flow maldistribution, manifold heat transfer increases overall effectiveness roughly as would be expected by the greater heat transfer area in the manifolds. Manifold heat transfer coupled with flow maldistribution for the prototype, however, causes a decrease in the effectiveness at high flow rate, and an increase in effectiveness at low flow rate.

Low and medium temperature thermal energy with temperatures of 100 to 150 C is available from renewable energy sources such as solar thermal or geothermal energy. Recent progress in flat plate solar thermal collector technology indicates that economical solutions for this temperature range are now becoming possible. Current technologies to generate mechanical energy from this temperature bracket such as Organic Rankin Cycle machines are however complex, and therefore only economical for larger units. There is a need for a simple, cost-effective medium temperature thermal engine for small-scale applications. Recently, the atmospheric steam engine was re-evaluated for this application. The theory was extended to include a forced expansion stroke. This can increase the theoretical efficiency of the ideal engine from 6.5% to 20%. In order to assess this theory, a series of experiments was conducted at Southampton University. It was found that the isothermal expansion of steam, and its subsequent condensation, is possible. The experiments showed a maximum efficiency of 10.2% for an expansion ratio of 1:4, indicating the validity of the theory. A further increase of efficiency to approximately 17% appears possible. It was concluded that the atmospheric engine with forced expansion has development potential.

Today the demand of energy is increasing
tremendously, but available energy lacks in supply. Hence,
there is no option for proper and efficient utilization and
conservation of energy. In this paper, the main stress is given
on energy conservation by using technique of utilizing waste
heat. This paper presents a review of various works focused on
waste heat in industry for improving energy efficiency. In the
present scenario energy crises is a severe problem across the
globe. For the protection of global environment and maintain
ecological balance, energy saving is one of the most vital issue.
Therefore, it is essential that we should endeavor for waste
heat recovery by making significant and concrete effort.
Conservation of energy by waste heat recovery is the need of
hour. The different reviews based on the aspects of heat
recovery and the methodologies and technologies being
employed for its optimization in industries also study through
literature. The objective of this work is to hypothetical design
of heat recovery system in SO2 gas generation process.

THE POTENTIALS FOR BIO WASTE MANAGEMENT IN MACEDONIA
Zoran Sapuric, PhD 1,  Filip Ivanovski, PhD, 1 Vulnet Zenki, 2Ana Karanfilova – Maznevska, Msc, 3
1University American College, Skopje, Macedonia, 2South East European University, Tetovo, Macedonia, 3Ministry of Environment and Physical Planning Skopje, Macedonia,
Email:  sapurik@uacs.edu.mk;
ABSTRACT
Waste management is still one of the biggest environmental problems in Macedonia. Within this framework, bio waste is an extremely serious problem. The developed system of bio waste management can substantially improve the protection of the environment. Macedonia as a candidate state for membership of the European Union has an obligation to follow the Unions’ standards and to limit the quantity of bio waste on the landfills. Besides of that, land filling of bio waste is almost the only solution. The situation is more alarming taking into consideration that from 54 landfills, there is only one, that meets some contemporary environmental standards. Although the bio waste significantly contributes in the total amount of waste, there are no any positive results in the modernization of bio waste treatment. There were realized some projects for composting, mainly supported by foreign donors, but shortly after the completion of the projects the composting has stopped. The commitment to the intensive treatment of bio waste, stipulated in the strategic documents and legislation remain unrealized. The main goal of this paper is to analyze and to research possibilities for development of bio – waste management in Macedonia and through the SWOT analysis determines the obstacles and potentials for its development. The paper also makes efforts to stimulate further researches in this area and to give some recommendations for further activities.
Key words:  Bio waste, management, improvement, analysis, potentials, treatment.

This study explores the integration of a rotary thermal wheel into a wind tower system, specifically the effect of the rotation speed on the ventilation rate and heat recovery. Wind towers are capable of supplying recommended levels of supply air under a range of external conditions, integrating a rotary thermal wheel will cause a reduction in the air supply rates due to the blockage created by the wheel. Using Computational Fluid Dynamics (CFD) analysis, the air supply rate and heat transfer of the rotary thermal wheel have been calculated for a range of rotation speeds between 0 rpm – 500 rpm.

The recommended air supply rate of 8l/s/p is attained up to a rotation speed of 50 rpm; beyond this rotation speed the air supply rate is too low. The maximum temperature recovered across the rotary thermal wheel is measured as 1.77 °C at a rotation speed of 20 rpm. Using the two results gained from the analysis, an optimum operating range of the rotary thermal wheel can be determined between 5 rpm and 20 rpm. The technology presented here is subject to an international patent application (PCT/GB2014/052513)

A new kind of solid-liquid-solid cyclic phase change heat engine is presented with optional but highly recommended multiple cylinders aka multiple stages cascading powertrain. Unlike the traditional Rankine engine or Stirling engine, hereby the gaseous phase is prohibited, and the conventional turbine is abandoned too. Under the drive of heat flux, low expansion volume of the working Phase Change Material (PCM) replaces the high expansion volume of hot gas, and in compensation, high expansion pressure replaces the low expansion pressure of hot gas. Via the isolated transformation from PCM pressure to hydraulic oil pressure, plus fluidic AC-DC rectification, a standard hydraulic motor replaces the gas or steam turbine. Multi-cylinder cascading heat engine can linearly increase up efficiency close to the ideal Carnot efficiency.

This paper presents a new design methodology of cross flow ventilated heat sinks. An accurate design of both finned and circular pin system with inline configuration has been produced. The model is based on the well tested experimental lumped parameter analysis of cross-flow heat exchangers by Gnielinski. The presented method is intended to support the design of heat sinks with well defined performances of cross flow ventilated heat sinks. An evaluation of the physical properties of the sink is performed and different cases are calculated. They allow comparing the performance in terms of both geometrical parameters of the exchanger and air speed. An effective model of the equations is produced and on this basis a multi-objective optimization is performed.

La propuesta persigue cinco objtivos, entre ellos: 

i)Desarrollar un prototipo de máquina tortilladora para uso en áreas rurales, ecológica, utilizando una combinación óptima de fuentes convencionales/fuentes alternas de energía;

ii) Determinar la factibilidad integral de que, para el 1° de enero del 2004, inicie operaciones a escala industrial la nueva compañía  “José Artemio Ulloa, Maquínas Industriales Tortilladoras, Sociedad Microindustruaial de Responsabilidad Limitada”, orientada al mercado del territorio cubierto por la puesta en marcha del Plan Puebla Panamá.

El pago para cubrir la facturación mensual de energía elécrtica del último lustro, de las plantas de ZZZZZZZ1 y YYYYYYYY, observa una creciente proporción.  Impacta negativamente, cada vez más, los costos globales de XXXXXX SA de CV y obstaculiza la posición de liderazgo de la empresa en el mercado estadounidense americano2.  Se requiere establecer estrategias e introducir mejoras puntuales, capaces de ahorrar y eficientar –de manera verificable- los sistemas de energía que actualmente se emplean.  A satsisfacer este requerimiento, tomando como punto de partida la planta de ZZZZZZZ, Edomex, es que se orienta la presente propuesta.

Cogeneration power plants simultaneously generate power and usable heat in a single, integrated system, which achieves a degree of overall efficiency that is much greater compared to electricity production alone. This makes better use of energy conversion and reduces greenhouse gas emissions. Combined heat and power production is already relatively common in Europe while it is less common, for example, in the USA. There is great potential for further implementation throughout Europe and worldwide, including in the industrial sector. Major challenges are the short potential distances for the transport of heat and the fact that consumers’ heat demands vary in quantity, mainly due to seasonal effects, and in quality as different applications require different temperature levels. Cleaner production schemes offer suitable frameworks to foster uptake of combined heat and power production by industry, in particular by small and medium sized enterprises.

Die Erfindung betrifft eine Vorrichtung aus einer mit einem Wärmeträgermedium beheizten Arbeitsfläche, die sich auf einer wärmeleitenden Deckschicht befindet, die von einem metallischen Grundkörper getragen ist. Die Deckschicht und der Grundkörper bilden einen " Trockenzylinder bestehend aus einem koaxialen Doppelzylinder und einem Ringspalt " , der vom Wärmeträgermedium durchströmt ist. Die Deckschicht ist mit einer Anzahl von Nuten, Rillen versehen und die Beheizung der Arbeitsfläche durch Zufuhr des Wärmeträgermediums vornehmlich in den Nuten, Rillen erfolgt. Die Deckschicht wird weiterhin " innengerillter Zylindermantel " genannt. Es werden folgende Varianten der Ausführung näher beschrieben: • Vorrichtung einer beheizten gerillten Zylinderinnenfläche • Trockenzylinder aus metallisch plattierter Mantelschicht • Trockenzylinder mit geringem spezifischem Wärmeinhalt

We present a video compression framework that has two key features. First, we aim at achieving perceptually lossless compression for low frame rate videos (6 fps). Four well-known video codecs in the literature have been evaluated and the performance was assessed using four well-known performance metrics. Second, we investigated the impact of error concealment algorithms for handling corrupted pixels due to transmission errors in communication channels. Extensive experiments using actual videos have been performed to demonstrate the proposed framework.

— During the pre-monsoon months in Nepal, severe thunder and hailstorms cause significant property and agricultural damage in addition to loss of life from lightening. Forecasting thunderstorm severity remains a challenge even in wealthy, developed countries that have modern meteorological data gathering infrastructure, such as Doppler Radar. This study attempts to isolate the specific and unique characteristics of the two hailstorms that might explain their severity. The primary data sources for this investigation included Infrared Satellite images, which illustrated the sequences of convective activity, and original archived ESRL India and China upper air data, which were used for synoptic and mesoscale analyses. Keywords—Pre-Monsoon Thunderstorms, Heat Lows.

This article presents a newly designed and realized system for heat recovery from waste water. The waste water is the heat source, the temperature of which is about 44-49 o C. The heat recovery process is performed using a plate heat exchanger and two heat pumps. The mentioned components are serially linked. The heat sink is clean water which is pumped from a 40 meter deep well and is heated up from 13-14 o C to 50-55 o C. Waste water is cooled down from 44-49 o C to 13-14 o C. The mass flow rate of the clean and waste water is approximately the same. This heat recovery process reaches a significant coefficient of performance (COP) with 6.03-6.5 meaning that 83-85% of the energy demand for heating clean water is provided by the recovery processand electric energy is consumed only for 17-15%. From the aspect of energy efficiency: the plate heat exchanger participates by about 49%, the low temperature heat pump by 30%, the high temperature heat pump by 21% in the heat recovery.

Existing buildings require optimization of the individual heating systems to decrease the energy consumption or energy use intensity (EUI) with heat recovery systems to maintain the sustainability. In terms of energy use intensity, hospitals are considered as the second highest EUI among diverse types of buildings. Therefore, to decrease energy use intensity in hospitals heat recovery options have to be analysed. In this application, oil-free air compressors' waste heat is recovered by using air-to-water heat pumps for providing hot tap water (around 10% of total) during summer mode and heating water for radiators placed in an emergency waiting room (42 m² area) during winter mode at Gazi University Hospital, in Turkey. The results showed that previously the unserviceable area get in use with a PMV value of +1. The payback period for the implemented system is found to be 2-4 years depending on heat load variations.

The treated sewage sludge under consideration is a hygienized biodegradable waste in the form of pellets. It can be used as a fertilizer, but only for spreading on non-agricultural land. Regarding "waste to energy" philosophy, the specification of pellets as an alternative solid fuel according to EN 15359 resulted in "NCV4; Cl1; Hg3-4" class. The major problem regarding the final pellets utilization is the lack of facilities for energy and material recovery from this type of waste in Slovenia. According to the newest legislation regarding the waste management, a product status for residues generated in combustion and pyrolysis of pellets on a laboratory and semi-pilot scale was not achieved. The holistic approach to final pellets utilization was studied and regarding the fullscale level of self-sufficient sewage sludge management in Slovenia, some legislative provisions become significant obstacles.

A finite difference model of a heat exchanger (HX) considered maldistribution, axial conduction, heat leak, and the edge effect, all of which are needed to model a high effectiveness HX. An HX prototype was developed, and channel height data were obtained using a computerized tomography (CT) scan from previous work along with experimental results. This study used the core geometry data to model results with the finite difference model, and compared the modeled and experimental results to help improve the expanded microchannel HX (EMHX) prototype design. The root mean square (RMS) error was 3.8%. Manifold geometries were not put into the model because the data were not available, so impacts of the manifold were investigated by varying the temperature conditions at the inlet and exit of the core. Previous studies have not considered the influence of heat transfer in the manifold on the HX effectiveness when maldistribution is present. With no flow maldistribution, manifold heat transf...