Abstract
The number of solar cooling, heating and hot water supply systems has been increasing steadily in Japan in these recent years. The performance of such systems, however, is dependent on a number of factors, and it is very difficult to foresee how each piece of equipment will perform as a part of the system even when the performance of individual equipment is known beforehand. At present, only few papers can be found which deal with the quantitative analysis of effects of various factors on energy saving and economy as described in this report. Although economic advantages of solar cooling, heating and hot water supply systems are not firmly established at this stage, attempts have been made in this paper to pinpoint what sorts of impacts are necessary to make such systems econmically feasible, with such parameters as future energy cost, equipment durability, system cost reduction, system performance improvement and available financial aid being taken into consideration. Assumed for this study was a solar cooling, heating and hot water supply system as applied to a 100m^2 dwelling house forming one unit of a semi-detached house. A total of nine factors which were thought to be importantly involved in the system design were selected for analysis. These nine factors were: locality; collector area (both of which have four levels); insulation properties of the building; thermal storage capacity; insulation properties of thermal storage; design temperature; locations of back-up heater; orientation of collectors; and inclination of collectors (all of which have two levels). Possible combinations of these factors amount to as many as 2048; however, by the use of DOE method, the number of factor combinations to be computed was reduced to only 64. The systems subjected to the analysis were simplified models each composed of one pane selective surface collector, a thermal storage, an auxiliary heater, pumps, and room units. For the systems serving also a cooling purpose, a hot water heated absorption chiller and a cooling tower were added. Hourly cooling and heating loads were obtained by the inconstant heat load calculations. Using such loads as input, system simulation was carried out to compute heat collected, auxiliary heat, power consumption by pumps, heat loss from the thermal storage and piping, and so forth. In this present report, the outline of the DOE and the algorithm of mathematical models will be described. The results of the experiment and the analysis thereof will be reported in the succeeding paper. It is to be noted that the study described in this paper was made as a part of the research studies for 1977 as conducted by SHASE (Japan)'s Committee for solar Heating-Cooling Systems which was commissioned by Ministry of International Trade and Industry (MITI) to perform such research studies under MITI's Sun Shine Project.
