In the field of air source heat pumps and hot water units engineering, Hien, the "big brother", has established itself in the industry with its own strength, and has done a good job in a down-to-earth manner, and further carried forward the air source heat pumps and water heaters. The most powerful proof is that Hien's air source engineering projects won the "Best Application Award of Heat Pump and Multi-Energy Complementation" for three consecutive years at the annual meetings of the Chinese Heat Pump Industry.
In 2020, Hien's domestic hot water energy-saving service BOT project of Jiangsu Taizhou University Phase II Dormitory won the "Best Application Award of Air Source Heat Pump and Multi-energy Complementation".
In 2021, Hien's project of air source,solar energy, and waste heat recovery multi-energy complementary hot water system in the Runjiangyuan Bathroom of Jiangsu University won the "Best Application Award of Heat Pump and Multi-energy Complementation".
On July 27, 2022, Hien's domestic hot water system project "Solar Power Generation+Energy Storage+Heat Pump" of the Micro Energy Network in the west campus of Liaocheng University in Shandong Province won the "Best Application Award of Heat Pump and Multi energy Complementation" in the seventh heat pump system application design competition of the 2022 "Energy Saving Cup".
We are here to take a close look at this the latest award-winning project, Liaocheng University’s "Solar Power Generation+Energy Storage+Heat Pump" domestic hot water system project, from a professional perspective.
1.Technical Design Ideas
The project introduces the concept of comprehensive energy service, starting from the establishment of multi energy supply and micro energy network operation, and connects energy supply (grid power supply), energy output (solar power), energy storage (peak shaving), energy distribution, and energy consumption (heat pump heating, water pumps, etc.) into a micro energy network. The hot water system is designed with the main goal of improving the comfort of students' use of heat. It combines energy- saving design, stability design and comfort design, so as to achieve the lowest energy consumption, the best stable performance and the best comfort of students' use of water. The design of this scheme mainly highlights the following features:
Unique system design. The project introduces the concept of comprehensive energy service, and constructs a micro energy network hot water system, with external power supply+energy output (solar power)+energy storage (battery energy storage)+heat pump heating. It implements multi energy supply, peak shaving power supply and heat generation with the best energy efficiency.
120 solar cell modules were designed and installed. The installed capacity is 51.6KW, and the generated electric energy is transmitted to the power distribution system on the bathroom roof for grid connected power generation.
A 200KW energy storage system was designed and installed. The operation mode is peak-shaving power supply, and the valley power is used in the peak period. Make the heat pump units run in the period of high climate temperature, so as to improve the energy efficiency ratio of the heat pump units and reduce the power consumption. The energy storage system is connected to the power distribution system for grid-connected operation and automatic peak shaving.
Modular design. The use of expandable construction increases the flexibility of expandability. In the layout of air source water heater, the design of reserved interface is adopted. When the heating equipment is insufficient, the heating equipment can be expanded in a modular way.
The system design idea of separating heating and hot water supply can make the hot water supply more stable, and solve the problem of sometimes hot and sometimes cold. The system is designed and installed with three heating water tanks and one water tank for hot water supply. The heating water tank shall be started and operated according to the set time. After reaching the heating temperature, the water shall be put into the hot water supply tank by gravity. The hot water supply tank delivers hot water to the bathroom. The hot water supply tank only supplies hot water without heating, ensuring the balance of hot water temperature. When the temperature of the hot water in the hot water supply tank is lower than the heating temperature, the thermostatic unit starts to operate, ensuring the hot water temperature.
Constant voltage control of frequency converter is combined with timed hot water circulation control. When the temperature of the hot water pipe is lower than 46 ℃, the hot water temperature of the pipe will be automatically raised by circulation. When the temperature is higher than 50 ℃, the circulation will be stopped to enter the constant pressure water supply module to ensure the minimum energy consumption of the heating water pump. The main technical specs are as follows:
Water outlet temperature of heating system: 55℃
Temperature of insulated water tank: 52℃
Terminal water supply temperature: ≥45℃
Water supply time: 12 hours
Design heating capacity: 12,000 persons/day, 40L water supply capacity per person, total heating capacity of 300 tons/day.
Installed solar power capacity: more than 50KW
Installed energy storage capacity: 200KW
2.Project Composition
The micro energy network hot water system is composed of external energy supply system, energy storage system, solar power system, air source hot water system, constant temperature & pressure heating system, automatic control system, etc.
External energy supply system. The substation in the west campus is connected to the power supply of the state grid as a backup energy.
Solar power system. It is composed of solar modules, DC collection system, inverter, AC control system and so on. Implement grid connected power generation and regulate energy consumption.
Energy storage system. The main function is to store energy in valley time and supply power in peak time.
Main functions of air source hot water system. The air source water heater is used for heating and temperature rise to provide students with domestic hot water.
Main functions of constant temperature and pressure water supply system. Provide 45~50 ℃ hot water for the bathroom, and automatically adjust the water supply flow according to the number of bathers and the size of water consumption to achieve uniform control flow.
Main functions of automatic control system. The external power supply control system, the air source hot water system, the solar power generation control system, the energy storage control system, the constant temperature and constant water supply system, etc. are used for automatic operation control and micro energy network peak shaving control to ensure the coordinated operation of the system, linkage control, and remote monitoring.
3.Implementation Effect
Save energy and money. After the implementation of this project, the micro energy network hot water system has a remarkable energy-saving effect. The annual solar power generation is 79,100 KWh, the annual energy storage is 109,500 KWh, the air source heat pump saves 405,000 KWh, the annual electricity saving is 593,600 KWh, the standard coal saving is 196tce, and the energy saving rate reaches 34.5%. Annual cost savings of 355,900 yuan.
Environmental protection and emission reduction. Environmental benefits: CO2 emission reduction is 523.2 tons/year, SO2 emission reduction is 4.8 tons/year, and smoke emission reduction is 3 tons/year, the environmental benefits are significant.
User reviews. The system has been running stably since the operation. The solar power generation and energy storage systems have good operation efficiency, and the energy efficiency ratio of the air source water heater is high. Especially, the energy saving has been greatly improved after the multi-energy complementary and combined operation. Firstly, energy storage power supply is used for power supply and heating, and then solar power generation is used for power supply and heating. All heat pump units operate in the high temperature period from 8 a.m. to 5 p.m., which greatly improves the energy efficiency ratio of heat pump units, maximizes heating efficiency and minimizes heating energy consumption. This multi-energy complementary and efficient heating method is worth popularizing and applying.
Post time: Jan-03-2023