ABSTRACT
The study presents a new analytical model capable to reveal the thermal behaviour of all the components of the solar ammonia-water absorption system, powered by parabolic trough collectors, serving different types of food storages: refrigeration chamber, refrigerated food storage, freezing chamber and frozen food storage. The heat inputs, that determine the total cooling load, for each food storage spaces consist of: heat gains through walls, heat gains through ventilation (fresh air), heat that must be dissipated from the stored products (technological cooling load required to cool down the products) and heat gains through operation. The influence of the number of solar parabolic trough collectors and of the storage tank size on different parameters of the refrigeration plant are investigated under low and high storage temperatures.â¢Food cooling with solar absorption refrigeration system.â¢Hourly based variation of NH3-H2O solar absorption system performances.â¢Long term simulation of solar absorption cooling for refrigeration and cooling.
ABSTRACT
The study proposes a method for preliminary and estimative sizing of the main components of solar district heating systems, with seasonal thermal storage. The main parameters determined by this method, are the aperture area of the solar thermal collectors and the volume of the seasonal thermal storage. The proposed method is only estimative, but it provides the necessary input data for the investigation ofthe dynamic thermal behavior of such systems. The main advantage of the method is that it requires only very few and accessible input data. Two situations are considered: the first in which available climatic data such as annual global solar radiation on horizontal plane and annual average temperature can be used in calculations, and the second in which such data is not available and should be determined through interpolation. With the proposed interpolation functions the annual global solar radiation on horizontal plane, the annual average temperature and the annual global efficiency of the solar thermal collectors were determined. The errors of the estimations are ranging within the intervals of (-15.6 +25.8) % for annual global solar radiation on horizontal plane and (-10.8 19.1) % for annual global efficiency of the solar thermal collectors. The maximum deviations for the annual average temperature estimations were (-4.23 +5.37) °C. With this limited accuracy, the proposed interpolation functions can be used for latitudes between (0-70) °, annual global solar radiation on horizontal plane between (704-2337) kWh/m2/year and annual average temperatures ranging within the interval of (2-30) °C.
