Application Guide for 25-Ton Solar System (Unitized)

摘要

Arkla has developed a unitary solar system for air conditioning, heating and service hot water loads in commercial buildings of up to 25 tons cooling requirement. A semi-exploded view shows the basic elements of the Arkla system. These elements, listed below, are described in individual sections of the guide in sufficient detail to enable a competent designer to duplicate the Arkla unitary system in a site built system. The elements are: (1) collectors with summary procedure guide; (2) storage/receiver; (3) pumps/piping/valves; (4) controls; (5) chiller; (6) cooling tower; (7) gas boiler back-up; (8) central air handling unit; and (9) service and DHW. Any successful solar HVAC system requires careful analysis of the integration of the elements. This is particularly true due to the large year-round variation in the temperature of the solar HW available. Several items of this nature are discussed in the element sections. Consequently, the designer should review this entire guide before proceeding to individual elements particularly A and B. This guide presumes that the monthly (and design) hot water loads have been determined for the heating, cooling, and service-DHW water Btu requirements. In addition to these normal calculations, an hourly profile for a typical day each month should be made. The hourly profile is necessary to maximize the solar fraction for a given amount of collector surface in conjunction with the size of the storage system; that is, the coincidence, or lack of, sunshine to the instantaneous demands. (ERA citation 08:040533)