The Research And Development Of Control System For Air-sourced CO₂Heat Pump Water Heater

The rapid development of economy brings us not only a wealth of material comfort, but also a difficult issue of energy and environment. Hot water, which is a necessity of building heating and manufacturing production, possesses a large proportion of the global energy consumption. If a new water heating method that is efficient in using energy and pollution-free could be found, it would have far-reaching significance in solving the issue of energy and environment. The air-sourced carbon dioxide heat pump water heater’s energy efficiency is much higher than traditional water heater, for its unique operating principle, as well as little waste discharge. It is the two aspects that meet the need of the modern times.The task of this project is to develop a set of control system of air-sourced carbon dioxide heat pump. First, design control system hardware, including main circuit, control circuit and the selection of modules in system. Then write heat pump unit configuration based on MCGS to display unit’s operating status with its user-friendly interface. Finally, create the control strategy of heat pump, including start and end strategy, defrost, and treat fault. Besides, writing corresponding program, and passing the testing with excellent performance are indispensable parts.This set of control system can guarantee the efficiency and stability of the heat pump unit’s operation, even keep COP up to3.3under ambient temperature25℃.The methods of troubleshooting, temperature and pressure control by this paper can guarantee the operation of heat pump is in a continuous, efficient and safe state without operators.This set of control system not only guarantees high COP of the heat pump unit, but also makes the control system have a good versatility by using close-loop control mode. It will lead a good guidance to other control system of heat pump, and even contribute to the promotion of heat pump water heater in the future.