{"title":"Heat pumps in industry—I. Equipment","authors":"Renato M. Lazzarin","doi":"10.1016/0890-4332(94)90029-9","DOIUrl":"10.1016/0890-4332(94)90029-9","url":null,"abstract":"<div><p>Industrial heat pumps are reviewed, classifying them according to the way by which the working fluid is taken from the lower to the higher pressure: mechanical or thermal. Each group is further subdivided in closed and open cycle. The most recent technological developments are considered for each classification.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 581-597"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90029-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80723030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Henrik Madsen, Ken Sejling, Henning T. Søgaard, Olafur P. Palsson
{"title":"On flow and supply temperature control in district heating systems","authors":"Henrik Madsen, Ken Sejling, Henning T. Søgaard, Olafur P. Palsson","doi":"10.1016/0890-4332(94)90031-0","DOIUrl":"10.1016/0890-4332(94)90031-0","url":null,"abstract":"<div><p>This paper discusses how the control of the flow and the supply temperature in district heating systems can be optimized, utilizing stochastic modelling, prediction and control methods. The main objective is to reduce heat production costs and heat losses in the transmission and distribution net by minimizing the supply temperature at the district heating plant. This control strategy is reasonable, in particular, if the heat production takes place at a combined heat and power (CHP) plant. The control strategy is subject to some restrictions, e.g. that the total heat requirement for all consumers is supplied at any time, and each individual consumer is guaranteed some minimum supply temperature at any time. Another important restriction is that the variation in time of the supply temperature is kept as small as possible. This concept has been incorporated in the program package, PRESS, developed at the Technical University of Denmark. PRESS has been applied and tested, e.g. at Vestkraft in Esbjerg, Denmark, and significant saving potentials have been documented. PRESS is now distributed by the Danish District Heating Association.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 613-620"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90031-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88065183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy conservation aspects in Indian thermal power stations by technological innovations: Experience and prospectives","authors":"I.P.S. Paul , S.C. Kaushik , S.P. Sabberwal","doi":"10.1016/0890-4332(94)90034-5","DOIUrl":"10.1016/0890-4332(94)90034-5","url":null,"abstract":"<div><p>The work presents the analysis of the concentrated efforts put in by Indian technologists for harnessing maximum energy from thermal power stations (TPS). The prime objectives have been to extract maximum energy from coal. All the controllable losses should be minimized in all operations and systems. Model outlines and practices followed by energy efficient power stations have been summarized. Measures to consume the least possible steam, materials, and petroleum products have been studied in detail. The role of condenser vacuum, excess air, all types of auxiliary (works) power, and an energy audit have been investigated in maximizing power generation. Approaches either to renovate, repair or retrofit or replace the ageing components having poor economic performance with modern technologies have been illustrated. The present system and technologies would be obsolete and economically and enegy-wise highly inefficient by the turn of the century. Thus developed/currently advanced and futuristic (under advanced stages of development) technologies have been listed for applications now or later. In spite of spending 20% of total planned expenditure since 1950 on power, the significance of energy conservation for bridging the energy gap should remain on the top of the Indian energy alternatives list, according to the conclusions of the present study.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 639-649"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90034-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81542095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Absorption heat-pump regeneration in a rankine steam cycle","authors":"N. Jawahar , S. Kumar","doi":"10.1016/0890-4332(94)90030-2","DOIUrl":"10.1016/0890-4332(94)90030-2","url":null,"abstract":"<div><p>This paper presents a system of regenerative heating incorporating an absorption heat pump in a Rankine steam cycle which can improve cycle efficiency. A simulation has been performed to estimate the Rankine cycle efficiency in the proposed Absorption Heat Pump Regeneration (AHPRG) heating system using the working pair R21<span><sup>‡</sup></span>-DMETEG. The results show that the cycle efficiency can be improved considerably without reducing the work output by the incorporation of AHPRG for low-temperature heating of steam condensate. Further, the temperature of the heat-pump evaporator which absorbs the heat rejected at the steam condenser plays a predominant role in the cycle efficiency.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 599-612"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90030-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80713000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation of liquid dessicant based evaporative cooling cycles for typical hot and humid climates","authors":"Sanjeev Jain , P.L. Dhar , S.C. Kaushik","doi":"10.1016/0890-4332(94)90032-9","DOIUrl":"10.1016/0890-4332(94)90032-9","url":null,"abstract":"<div><p>This communication presents an evaluation of various liquid dessicant cycles for air conditioning in hot and humid climates. Psychometric evaluation of seven potential cycles for achieving standard comfort conditions (25°C/10 g/kg) in rooms has been carried out for 16 typical Indian cities. A computer simulation model is based on the constant effectiveness of heat exchangers (HX)/evaporative coolers (EC) and wet surface heat exchangers (WSHE). The absorber-cum-dehumidifier is assumed to provide air at the specified humidity level, while the outlet air temperature is taken to be equal to the cooling water temperature. The effect of various outdoor conditions and the effectiveness of HXs/ECs on cooling COP and volumetric air flow rate per unit cooling capacity have been investigated. It was found that a combination of dehumidifier and WSHE is better, in terms of COP, for a wide range of outdoor conditions. The results should be useful in the design of liquid dessicant based air conditioning systems suitable for the monsoon season in tropical countries like India.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 621-632"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90032-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73360183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimum operating temperature and efficiency of solar thermal power systems","authors":"N. Singh, S.C. Kaushik","doi":"10.1016/0890-4332(94)90033-7","DOIUrl":"10.1016/0890-4332(94)90033-7","url":null,"abstract":"<div><p>In this paper, finite-time thermodynamics has been applied to solar heat engines in order to find the optimum operating temperature for solar thermal power systems. The percentage difference between optimum operating temperatures based on Curzon-Ahlborn (CA) efficiency and classical Carnot efficiency has been presented. This analysis has also been used to find the upper bound on efficiency for a wide range of the operating temperatures characterising various solar thermal power systems.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 6","pages":"Pages 633-638"},"PeriodicalIF":0.0,"publicationDate":"1994-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90033-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78135814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical analysis of compact air condensers","authors":"P. Tartarini, E. Lorenzi, G.L. Morini","doi":"10.1016/0890-4332(94)90056-6","DOIUrl":"10.1016/0890-4332(94)90056-6","url":null,"abstract":"<div><p>The present work aims at analysing the thermal behaviour of the vapour flow inside the horizontal tube bundle of a cross-flow air condenser. It is pointed out that the steady-state air and water temperature distribution cannot be determined by means of analytical solutions, due to the non-linearuty of the problem. A model based on appropriate balance equations is introduced and a finite difference computer code is formulated. This code, which reports a large number of correlations found in the literature, is used to evaluate the different flow patterns that characterise the two-phase flow condensation. It is also employed to calculate the local heat transfer coefficient, for both air and water side, and the pressure drop on the water side. The main results, related to the evaluation of the condenser's thermal-hydraulic behaviour (pressure and temperature of the condensing fluid), are presented and discussed in detail.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 5","pages":"Pages 535-547"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90056-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85554502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Barriquand all welded plate heat exchanger type platular (R)","authors":"D. Martin","doi":"10.1016/0890-4332(94)90059-0","DOIUrl":"10.1016/0890-4332(94)90059-0","url":null,"abstract":"<div><p>Technological evolution in welding processes and the successful appearance on the market of stainless steel able to operate under extreme service conditions, together with an increasing demand for compact heat exchangers combining efficiency, reliability and versatility, have led to the development, over 25 yr, of all welded plate heat exchangers named and patented under the registered trade name: PLATULAR.</p><p>This paper gives the background to the introduction of these units, as well as the latest developments in the field of heat transfer: combining multi-streams in a single unit. Some examples are illustrated to more clearly explain the real advantages of this technique.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 5","pages":"Pages 563-573"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90059-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73149758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Some effects of air flow maldistribution on performance of a compact evaporator with R134a","authors":"David J. Timoney, Patrick J. Foley","doi":"10.1016/0890-4332(94)90054-X","DOIUrl":"10.1016/0890-4332(94)90054-X","url":null,"abstract":"<div><p>An experimental facility has been constructed to enable the effects of air flow non-uniformity on the transfer performance of refrigerant evaporators to be investigated. This is based on an open-circuit wind tunnel, which is equipped with a single component traversing LDA system, capable of determining local mean velocities and turbulence levels. The refrigerant circuit uses R134a and has been designed to allow maximum flexibility in setting test conditions.</p><p>Preliminary results are presented from tests on a single circuit finned-tube evaporator with 33 tubes, 300 mm long, arranged in an in-line matrix 4 rows deep, with 25 mm spacing. The height of the fin block was 225 mm, the fin spacing and tube external diameter were 4 mm and 9.5 mm respectively.</p><p>Contrary to expectations, <em>increases</em> in heat transfer duty and overall heat transfer coefficients were recorded as air flow non-uniformities were artificially introduced, whilst a constant mean air velocity was maintained.</p></div>","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 5","pages":"Pages 517-523"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90054-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89246068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Human capital and mobility programme","authors":"","doi":"10.1016/0890-4332(94)90062-0","DOIUrl":"https://doi.org/10.1016/0890-4332(94)90062-0","url":null,"abstract":"","PeriodicalId":100603,"journal":{"name":"Heat Recovery Systems and CHP","volume":"14 5","pages":"Page 576"},"PeriodicalIF":0.0,"publicationDate":"1994-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0890-4332(94)90062-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137010474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}