Research On Thermal Condition Of Hot Water Heat-supply System

As our country paying more attention to energy conservation and emission reduction mission, it's more valuable to research on hot water heat-supply system for the further study. How to avoid overheating of the heat consumers under the guarantee of heating quality, in order to improve energy efficiency of central heating system, becomes an important research subject.This paper discussed on thermal conditions change regulation of the hot water supply system and methods to eliminate thermal maladjustment of heat consumer, based on the establishment of mathematical calculation model for thermal conditions of the system.Firstly, this paper established a three dimensional topology for thermal conditions calculation model, based on fluid network analysis theory. Through the steady thermal characteristics analysis of direct connection and indirect connection hot water heat-supply system as well as the dynamic thermal characteristics analysis of direct connection hot water heat-supply system, an unified steady thermal conditions mathematical calculation model of direct connection and indirect connection hot water heat-supply system and a dynamic thermal conditions mathematical calculation model of direct connection were founded.The influence on steady thermal conditions of direct connection hot water heat-supply system and dynamic thermal conditions of indirect connection hot water heat-supply system caused by pipeline heat loss were analyzed, on the basis of study on calculation method of temperature drop per unit length of directly buried pipe. With the analysis of thermal maladjustment degree of heat consumer, constant-variable flow control plans were proposed according to features of the system, also the feasibility and significance of these plans were analyzed from the point of view of energy saving. Through the analysis of the results the necessity is proved that system of poorer heat preservation need to be adjusted, and it was proved that there is an advantage for adjusting on user's flow side at the heat exchange station of the indirect connection system when thermal disorders was caused by primary circuit pipe heat loss.The study researched on dynamic change regulation of thermal conditions, according to the change of heat source outlet water temperature and hydraulic condition changes caused by closing down of pipe valve at the heat consumer.. And it also studied the delay of Thermal conditions reaction influenced by passing through time of the hot water in the network and the influence on average indoor temperature change process of heat consumer connected with thermal storage capacity.