Study On Some Issues Of Heat Metering Heating System

Heat metering is proposed by the strategy of the energy saving and environment protection, agrees with the demand of the dwells'thermal comfort. The thesis is focused on the design, operation and charging.By setting up the mathematic control model of the inner room temperature, analyzes the disturbing factors and points out that only the compensating control or only quantity control is not fully suitable for the metering heating system. By citing that the heat authority must be beyond 1, points out that metering heating system should apply the series control mode that central compensating control combines with the quantity control of TRV terminals.Analyzes how the flow variation affects the valve characteristic of terminal control valve by inciting the real valve authority. Setting up the mathematic control model of the inner room temperature for TRVs, turns out the formulas of the proportional band of the TRVs. Through the experiment and calculation, studies the valve characteristic and energy saving principle and affection of the TRVs.By analyzing how the flow variation and available differential pressure variation affect the heating system with variable speed pump and constant pump separately, points out that these problems above can not be solved by variable speed pump but only by applying the differential pressure controllers. Studies the control characteristic and the applying method of the differential pressure controllers. Analyzes the condition of constant flow users and variable flow within one heating system and sets forth the relative control methods. Analyzes the limit of the affinity law for centrifugal pumps and how the flow variation affects the efficiency of the pumps by drawing out the efficiency curve for variable speed pumps. Studies the allocation modes of variable frequency devices and analyzes the necessity of the flow and head limit for pumps. Compares the energy-saving affection and suitability for the heating system of the different control modes for variable speed pumps, sets forth the optimum control modes with multiple sites and sensors for variable speed pumps.Points out the principles of heat price and charging, and that the two parts for heat price is essential. Presents three methods for heat price and charging and the ways to revise the heat bill.