Chapter 231 - Influence of Climate Variation on Collector Output

Abstract

This chapter describes the influence of climate variation on collector output. Simulations of collector energy output are in most cases made with the same climate data, often a reference year or a simulated year. If the climate parameters are varied the influence of climate can be investigated. Simulations are made with climate data from 1983 to 1998 for Stockholm, Sweden, for two different collector types. The difference in annual delivered thermal energy between the individual years and the 1983 to 1998 average is up to +100 (kWh/m2, year) for an average collector temperature of 50°C. These large variations make it hard for the collector manufacturers to provide a meaningful guarantee of the annual collector energy output. A guarantee including the standard deviation is suggested. The annual energy output can be described with reasonable accuracy using the relation Q = aG(0°)+bT obtained with multiple linear regression. G is the global horizontal insolation, T is the collector temperature, and a and b are collector specific constants.