The comparison of calculation methods of gas demand in the installation with combi boilers

Abstract

Combi boilers offer an economic alternative to individual single function gas boilers and instantaneous water heaters. These gas appliances allow for producing thermal energy for two heating purposes (space heating and hot water preparation). For this reason these compact and highly efficient devices are becoming increasingly popular in many residential buildings. The application of such heating systems often requires an adequate approach for determining the natural gas demand. The literature indicates several methods for this purpose, which often differ significantly. Differences in calculated results seem to be the main problem with these methods. Unfortunately, the selection of the above-mentioned gas appliances always causes overestimation of natural gas demand. This is mainly due to the fact that many calculation methods contain incorrect gas demand coefficients. Therefore, this paper presents various methods for estimating gas consumption for multi-family buildings. It provides discussion and analysis of various calculation methods for residential buildings equipped with two types of gas appliance. The performed analysis made it possible to indicate the most reliable methods of gas demand calculation.