Consumer Heating System Simulation (CHESS)
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Introduction
The objective is to develop a dynamic simulation tool for consumer heating systems especially designed for district heating. Compared to traditional HVAC systems, those connected to district heating systems differ due to flow control and focus on temperature difference of the primary water. In this report two system concepts are described, one radiator system and one system for ventilation air heating. These two systems are combined as consumer installations and linked to a consumer substation heat exchanger. The total system concept is described.
Some test simulations are presented to give an idea of the alternative applications of the simulation tools.
Summary
CHESS is a PC-based dynamic simulation tool for Consumer Heating Systems especially designed for District Heating. The tool is also very useful for Heating Systems in general where a great cooling of the hot water is important like in systems with heat pumps.
The CHESS-concept is based on a modular structure where the system you want to analyze can be built together from separate models of the actual components in the system. The basic models take care of the effect of varying water flows and its influence on the heat transfer coefficients.
At this stage of the programme development the linking procedures have to be done by experts. More developing work is needed to enhance the user friendliness to a level where a non-expert may build his own system configurations. The programme in hand contains two separate executive program-versions of a chosen "reference system". These executive programmes may be operated very easily by non-experts.
The CHESS-concept may be used for several purposes like:
- Optimization of temperature differences and the water cooling in the system
- Evaluation the regulativity of the system
- Choosing the right regulator
- Adjusting the regulator
- Evaluating of regulating valves
- Choosing the right values
- Choosing the right place for the sensors
- Evaluating the regulating consequences of hysteresis etc
The concept makes it possible to evaluate the whole system operation on the designstage and thereby eliminate bad system configurations at an early stage. The CHESS-concept may also be used to analyze existing bad working systems to see the effects of possible changes of the system. The simulation program is adapted from a simulation tool named CYPROS SIM which is a program for solving nonlinear dynamic problems.
Ordering of diskette
A diskette with the executive programmes that are developed may be requested from the member of the "Executive Committee" from your own country.
The following reference is recommended:
"IEA-District Heating and Cooling Project", Annex III
"Consumer Heating System Simulation (CHESS) November 1992.
