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| NIRE Annual Report | 
| 1998 |
Efficient Space Cooling System using Diurnal Range of Atmospheric TemperatureThermal Energy Applications DivisionThermal Energy and Combustion Engineering Department |
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Objectives
There are many kinds of researches and applications using solar heat for space heating and cooling or supplying hot water. Most of them are active methods. Active methods have a good capability for space heating and cooling though they require some complicated equipment such as absorption chillers or solar collectors. On the other hand, passive methods have low space heating and cooling capacity though they require simpler equipment such as ventilators or thermal insulation. Neither system is totally appropriate for most part of Japan where insolation and heating loads are not so high but cooling loads are rather high.
This work aims at using the thermal energy from not only solar radiation but also ranges of atmospheric temperature as the alternative heat source for space heating and cooling. As the first step of the work, behavior of the system using diurnal range of atmospheric temperature in the summer is characterized by numerical simulation.
Results
The whole system is composed of some equipment shown in Fig. 1. In this report, the only elements drawn with solid lines in Fig. 1 are considered to characterize clearly the performance of the system. Parameters for the calculation are assumed from the actual weather condition and characteristics of energy equipment in Japan. From the calculation, it is found that there are optimum conditions to reduce the consumption of electric power for air-conditioning. For example, when the radiator is operated during some limited hours, the total consumption of electric power becomes smaller than that when the radiator is continuously operated throughout night as shown in Fig.2.
Selected Publications
1) Effective Heat Utilization of Diurnal Range of Atmospheric Temperature, Solar Engineering, J. H. Davidson and J. Chavez, ed., pp. 187-193, ASME, New York, 1996. 2) Effective Heat Utilization of Diurnal Range of Atmospheric Temperature with Stratified Thermal Energy Storage System, Proc. 32 Intersociety Ene. Conversion. Eng. Conf., 3, pp.1678-1683, AIChE, New York, 1997.
