摘要:

AbstractAn overall heat transfer coefficient was calculated for a forced draught counterflow cooling tower by using the pulse response technique. The presence of an axial dispersion coefficient for both gas and liquid was considered. Results indicate that, on neglecting the axial mixing and assuming a plug flow, the overall heat transfer coefficient is overestimated and can lead to errors in design applications.

ISSN:0363-907X    

DOI:10.1002/er.4440140202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper describes the development of a simple and handy microcomputer theoretical simulation model, suitable for investigation of the performance of a low cost solar heating system which is believed to be suitable for use under the local meteorological conditions.Hour by hour simulations have shown that substantial solar fractions can be achieved even in existing buildings, and the introduction of easily accessible daily mean meteorological data allows the investigation of the thermal performance and energy conservation in buildings for any location in Greece.

ISSN:0363-907X    

DOI:10.1002/er.4440140203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractCombined cycle systems have been recognized as efficient power systems in which exhaust gas from the topping cycle provides the available energy to the bottoming cycle. Since most heat sources available to the bottoming cycle are sensible‐heat sources, there may be a better thermal match, and an increase thermodynamic efficiency, on reducing the entropy generation of the simple combined cycle.To increase the efficiency of the Rankine cycle working with sensible heat, two conventional methods have been proposed: one is to incorporate a multipressure boiler; the other is to implement a supercritical cycle. An alternative method is to use a multicomponent working fluid boiling at a variable temperature with a change in the liquid composition of the components, and yielding a better thermal match with the sensible‐heat source than the constant temperature boiling process. The Kalina cycle is an implementation of this concept, where ammonia/water mixtures are used as the working fluid.The purpose of this study is to conduct a preliminary study of the Kalina power cycle system in connection with a combined cycle system, comparing the Kalina cycle and the Rankine cycle. This study is performed using new thermodynamic properties of ammonia/water mixtures developed by the auth

ISSN:0363-907X    

DOI:10.1002/er.4440140204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractSodium lauryl sulphate (NaLS), tetradecyl trimethyl ammonium bromide (TTAB) and Brij‐35 were used in a photogalvanic cell containing azur A as a photosensitizer and glucose as a reductant for solar energy conversion and storage. The photopotential and photocurrent generated by the cell in the presence of NaLS were 811.0 mV and 1470 μA, respectively. The effect of variation of the concentrations of the surfactants on the electrical output, the fill factor, the conversion efficiency and the performance of the cell in the dark was studied in deta

ISSN:0363-907X    

DOI:10.1002/er.4440140205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper is divided into two parts. In the first part, the results of tests on 13 stoves currently being marketed in India, compared with two traditional stoves, are presented. The bulk of the tests (about 140) pertain to variation of efficiency against fuel burning rate. Also, a few tests on the variation of chimney heights (18 tests) and damper position (20 tests) were conducted. The levels of efficiency were quite low on account of improper dimensioning of the stoves. Except for two stoves, all recorded consistently low efficiency figures.In the second part of the paper, the results of tests on combustion chambers of different sizes, ranging from a diameter of 180 mm to 500 mm, are presented in the form of design equations. The optimum length to diameter ratio is about 0.35, and optimum height of the ash chamber is 0.2 times the height of combustion chamber. A new approach to the sizing of combustion chambers is presented.

ISSN:0363-907X    

DOI:10.1002/er.4440140206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe net savings (cost of fuel saved minus the cost of additional thickness of wall and the singly glazed window of the south wall) by the use of a thicker wall and glazed window on the south side have been evaluated for the cold desert climate in India (typified by Leh in Ladakh); the traditional construction implies mud walls and room temperature maintained at 25°C or 17°C by burning Kerosene oil.The thickness of the south wall and the size of window on the south wall (of a 6 × 4 × 2.7 m3room) have been optimized for maximum savings, corresponding to room temperatures of 25°C or 17°C and the South wall made of mud or concrete; three outer finishes of the walls viz. bare natural, blackened and unglazed and blackened and glazed have been considered. Optimum insulation on the roof and the other three walls has been as

ISSN:0363-907X    

DOI:10.1002/er.4440140207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe paper describes a FORTRAN computer program, ISTORE, designed to simulate the optimum operation of an ice‐storage air‐conditioning system under a time‐of‐use electricity tariff. The model uses capital cost and operating cost data to optimise the sizes of the component chiller set and store for an annual operating cycle which can take into account several different seasonal load conditions. Where applicable, the model can also optimise settings for maximum electricity demand. The model provides comprehensive graphical and printed output which allows optimum control strategies to be quickly identified.An example study is given which indicates that considerable savings are available under a maximum demand tariff by using the ice‐storage technology as a load management device to reduce air‐conditi

ISSN:0363-907X    

DOI:10.1002/er.4440140208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe performance of a semiconductor septum electrochemical photovoltaic (SC‐SEP) cell based on electrodeposited CdSe thin films is reported. Photovoltages and photocurrent densities of 1.06 V and 15 mA/cm2, respectively, were obtained. The proper selection of the electrolyte/electrode combination in the back compartment is a key factor better performance. A low fill factor causes a relatively low conversion efficiency of about 3.5

ISSN:0363-907X    

DOI:10.1002/er.4440140209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440140210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractResults of a study to examine the operating characteristics of a 100 kWh thermal energy storage (TES) system suitable for solar thermo electric applications is described. The system chosen consisted of a pebble bed as the primary storage medium and oil as the heat transfer cum storage medium. The operating temperatures considered were between 230 and 250°C with a 20 deg C swing. A full‐size unit consisting of a steel tank of volume 10 m3with 50 mm pebbles, suitable instrumentation and facility for heating the oil was built. The important operating variables and characteristics of the system studied included the transient behaviour of the bed, namely the thermal wave front characteristics. Results of the theoretical analysis of the transient bed behaviour were compared with the experimental data on the wave front propogation characteristics and the comparisons are discussed. The uniformity of flow distribution is also examin

ISSN:0363-907X    

DOI:10.1002/er.4440140211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY