Analysis and Design of Solar Process Water Heating Systems without Storage for Industrial and Commercial Applications

Summary

In many industrial, commercial and institutional applications of solar process water heating, space available for locating collectors is limited. Because large amounts of process water heat are needed for these applications, the solar fraction (the percentage of total energy requirement that is supplied by solar energy) is low. The demand for process heat occurs mainly during daylight hours. As a result, most solar energy is used as soon as it is collected. The objective of this project is to determine under what conditions it is cost-effective to eliminate thermal storage from solar process water heating systems. Five actual buildings in the Southern Ontario area of Canada were selected. For each site, profiles for hourly and daily usage of process hot water were determined. For each situation, solar heating systems with and without storage were designed. For each system, construction cost estimates and estimates of solar energy collection were made. In a majority of the practical situations evaluated, it is cost-effective to design solar process water heating systems without storage. Generalised guidelines on the use of “zero-storage” systems are also presented.