Real Heating Network Research Articles

Efficiency of CHPP Operation in Heat-Supply Systems when the Transition to Lowered and Extended Schedules of Heating Regulation

The aim of the work is a theoretical study of the efficiency of heat supply based on a software package that includes mathematical models of a real CHPP, a real heating network and real heat consumers with a high share of hot water supply load using extended and reduced temperature schedules of heating regulation. The set aim is achieved by solving the following problems: choosing a method for calculating various schedules of regulating heat supply from CHPPs; construction of initial, reduced and extended temperature schedules and schedules of delivery water consumption; determination of optimal energy costs and heat-transfer agent costs. The most important of the results achieved is the carried analysis of the energy and economic efficiency indicators changes during the transition from the traditional to lowered and extended schedules of heat-supply system regulation. The total fuel savings at CHPP during the transition from the initial design temperature schedule with a maximum delivery water temperature of 150°C to the most energy efficient schedules reaches about 2%, which should be recognized as very significant. The significance of the obtained results lies in the fact that they allow calculating the energy effect in the form of fuel savings at CHPPs compared to their operation with the design temperature schedule. It is shown that the use of these technologies will increase the efficiency of district heating that will ensure a reliable and high-quality supply of heat energy to consumers and reduce its cost.

High-Resolution Modeling and Decentralized Dispatch of Heat and Electricity Integrated Energy System

The heat and electricity integrated energy system (HE-IES) has high energy efficiency and bright application prospects. In the HE-IES, the heat transmission in the heating network and the indoor temperature variation in the buildings are governed by (partial) differential equations, which bring the heat dynamics problem in the system operation. In this paper, we propose a comprehensive approach for the operation of the HE-IES to coordinate the electricity and heat dynamics, including modeling, evaluation, and dispatch procedure. First, we formulate a high-resolution model for the heating network and buildings to describe the heat dynamics; two indices are proposed to measure the impact of heat dynamics, which are then used to select the time resolution. Second, an optimal dispatch model with high resolution for the heat dynamics is formulated for the HE-IES; a decentralized and parallel solution method is proposed based on the alternating direction method of multipliers. Third, a two-stage procedure for the time resolution selection is proposed, which consists of a dispatch decision stage and a time resolution evaluation stage. A small illustrative case is studied to verify the effectiveness of the proposed method. A big case based on a real heating network in Jilin Province, China, is also simulated.