摘要:

AbstractAn observational study on the Wallasey School has demonstrated its ability to maintain in most conditions of climate an equitable indoor climate both in regard to daily mean temperatures and daily variations, through use of solar gain and heat from the lights, and the appropriate control of ventilation. During occupied periods, air temperatures are usually between 17°C in winter and 23°C in sunny summer periods. The room provides a mainly ‘cold wall’ environment. The observational data and a series of model estimates have been compared. The general level of temperature within the building is known to depend strongly on ventilation rate, but since ventilation rate was not measured, steady‐state comparisons as such are not possible. The observed and estimated temperature profiles for air and various surfaces including that of the furnishings during a very sunny period are in broad agreement.Analyses of the transient response of the structure in winter conditions has demonstrated a long response time (several days) describing the response of the enclosure, and a shorter response time of about half a day which describes the rate of settlement of internal temperature differences which may be initially present. Evidence is presented indicating low values for the convective heat transfer coefficient. An autocorrelational technique demonstrates that the thermal ‘memory’ of the classroom is much longer in winter than in summer. The response of the room during occupied and unoccupied periods is broadly similar, but conditions are rather more variable during

ISSN:0363-907X    

DOI:10.1002/er.4440100403

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

年代:1986

数据来源: WILEY

摘要:

AbstractExperiments have been carried out to determine the effect of absorber reflux on the performance of a water‐lithium‐bromide absorption cooler. The reflux ratio was varied for two mass flow rates of solution leaving the absorber and two absorber temperatures. It has shown that absorber reflux can be used to decrease both the temperature and the concentration in the generator. The coefficient of performance and heat loads tend to have optimum values at a particular reflux ra

ISSN:0363-907X    

DOI:10.1002/er.4440100404

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

年代:1986

数据来源: WILEY

摘要:

AbstractTorque associated with rotor stall is shown to be an important factor in the yaw behaviour of fixed pitch horizontal axis wind turbines (HAWT). For a given operating machine, the best performance occurs when the plane of rotation is perpendicular to the wind velocity for all wind speeds,V, less than a fixed value,V0. ForV>V0a velocity dependent torque yaws a free rotor to more efficient energy gathering positions provided the yaw torque exceeds the corresponding machine frictional torque. The optimum angular positions (yaw trajectories) computed from dynamic equilibrium considerations are compared with, and shown to be in satisfactory agreement with, solutions furnished by a model based on a postulated energy gathering function. The postulational approach developed is particularly useful because of its generality and simplicity in describing the performance of a HAWT. It is noted that although it is advantageous from a performance point of view to yaw the rotor to the optimum position corresponding to a given wind velocity established by either dynamic equilibrium or the energy gathering model, one must be aware of the accompanying increase in cyclic loading. On the other hand, maintaining the plane of rotation perpendicular to the wind velocity at all times could result in significant performance losses as well as fatigue problems in fixed pitch rotors, especially during stall conditions.

ISSN:0363-907X    

DOI:10.1002/er.4440100405

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

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents results of a comprehensive analysis of enhanced oil recovery (EOR) potential in the United States for the rest of this century and beyond with respect to potential production rates and ultimate oil recovery. The analysis is based on a resource database consisting of over 2500 reservoirs with approximately 325 billion barrels of the original oil in place and considers two technology cases: a base economic case and an advanced technology case, both with variable oil price assumptions and discounted cash flow rate of return. The results are presented in graphical form and include EOR potential in the United States in terms of ultimate oil recovery and production rate to the year 2013 for each major EOR group of technologies and under varying economic and technological scenarios. The main conclusion of the study indicates that EOR could increase the current domestic crude reserves by approximately 40 per cent for the base case and nearly double the production rate for the implemented technology case.

ISSN:0363-907X    

DOI:10.1002/er.4440100406

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

年代:1986

数据来源: WILEY

摘要:

AbstractA proposal is made for a non‐electric hydraulic pump driven by the temperature difference between two low‐level heats. The pump consists of a warm‐water boiler, a condenser and a pump chamber in which a balloon is installed. A difference in vapour pressure of a working fluid, such as Freon, between the boiler and the condenser makes the balloon repeat expansion and contraction, and consequently water is pumped up from under ground to the ground, for example. Open/shut operation of the valve is performed by the balloon's expansion‐contraction. Also, no auxiliary pumps are required at the boiler and co

ISSN:0363-907X    

DOI:10.1002/er.4440100407

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

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents a mathematical model of the performance of the salt gradient solar pond. A lumped parameter model of the upper convective zone, non‐convective zone and lower convective zone is used. This model enables the temperatures of the upper‐convective zone and the lower convective zone of the solar pond to be predicted. The experimental results agree well with theoretically predicted values. The major error in the theoretical results is due to the difference between the theoretical value of the solar radiation inside the water and that observed experimentally. It is found that the experimental value of the solar radiation at a depth of 90 cm is approximately 26 per cent of the total solar radiation falling on the solar pond surface, whereas the corresponding theoretical value is found to be 33 per cent. The results conclude that the lumped parameter model can be used as a simple model to predict the performance of the solar p

ISSN:0363-907X    

DOI:10.1002/er.4440100408

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

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper presents the results of tests concerning two assumptions about the surface zone of a solar pond. The first assumption is that the surface zone temperature of the solar pond is equal to the air dry bulb temperature, and the second one is that it is equal to the air wet bulb temperature. The surface zone temperature and the storage zone temperature are predicted by using a lumped‐parameter model. The experimental results of the surface zone conform well with theoretical values. The results indicate that the air dry bulb temperature is more accurate in winter‐time but that the errors generated by both assumptions are almost equal in the summer

ISSN:0363-907X    

DOI:10.1002/er.4440100409

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

年代:1986

数据来源: WILEY

摘要:

AbstractElectric and gas utilities (in the U.S.A.) bill their customers on a regular basis, usually monthly or bimonthly. These data provide a truly valuable information resource for energy conservation programme analysts and evaluators.This paper discusses ways to analyse such billing data. The starting point is the Princeton University score‐keeping model, which permits decomposition of total household energy use into its weather‐and non‐weather‐sensitive elements; the weather‐sensitive portion is assumed to be proportional to heating degree days. The score‐keeping model also allows one to compute weather‐adjusted energy consumption for each household based on its billing data and model parameters; this is the model's estimate of annual consumption under long‐run weather conditions.The methods discussed here extend the score‐keeping results to identify additional characteristics of household energy use. The methods classify households in terms of the intensity with which the particular fuel is used for space heating (primary heating fuel vs. supplemental heating fuel vs. no heating at all with the fuel). In addition, households that use the particular fuel for air conditioning are identified. In essence, the billing data and model results define household energy use ‘fingerprints’. The billing data and model results can also be used to identify and correct anomalous bills. Finally, the methods permit careful examination and analysis of changes in energy use from one year to another. They help explain why some households show anomalously large energy savings (e.g. they began using wood as a heating fuel during the second year) or negative energy savings (e.g. very high air conditioning energy use du

ISSN:0363-907X    

DOI:10.1002/er.4440100410

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

年代:1986

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440100411

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

年代:1986

数据来源: WILEY

摘要:

AbstractEffects of free convection currents and mass transfer on the unsteady flow of an electrically conducting and viscous incompressible fluid past an infinite vertical porous plate subjected to uniform suction, in the presence of transverse magnetic field, have been studied taking into account that the external flow velocity varies periodically with time in magnitude but not in direction. The effect of the induced magnetic field has been neglected. Approximate solutions to the transient flow, the amplitude and the phase of the skin‐friction and the rate of heat transfer have been derived. During the course of the discussion, the effects of the Grashoff numberGr, the modified Grashoff numberGc(depending on the concentration difference), the Schmidt numberSc, the Eckert numberEc, the magnetic field parameterM, and the frequency ω have been discuss

ISSN:0363-907X    

DOI:10.1002/er.4440100412

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

年代:1986

数据来源: WILEY