The project is located in Beijing, China, with a typical northern climate.
This project is a temporary living area on the construction site, and its main functions are accommodation and office.
According to the on-site investigation and drawings, there are 450 rooms of 18㎡ in this project, which need to meet the needs of cooling in summer and heating in winter.
According to the actual situation, two schemes, refrigerant air conditioning and air source heat pump can be adopted.

Adopting a low-temperature air source heat pump central air conditioning system is more energy-saving and money-saving!
It is more reasonable to adopt an air source heat pump central air conditioning system in this project!

This paper makes a comparative analysis of these two schemes:

1, the difference in working principle between air source heat pump and refrigerant air conditioner:

Air-source heat pumps and refrigerant air conditioners have the same working principle. They both provide cold and heat sources for the room by exchanging heat with the outside air. However, the heat exchange medium in the final process is different.

The traditional split air conditioner always uses refrigerant as the medium. Although the air energy also transfers heat through refrigerants, the low-temperature air source heat pump uses water for heat exchange in the final heat exchange stage. This means that air conditioning is a fluorine system cycle, while air source heat pump is a water system cycle. Air source heat pumps and refrigerant air conditioning are commonly referred to as fluorine machines and water machines.

2. Comfort difference between air source heat pump and refrigerant air conditioner:

No matter whether it is cooling or heating, the fluorine systems will absorb a lot of water from the air, resulting in dry air, which will make people have a hoarse throat and dry mouth, especially in winter.

However, there is no such problem in the water system, so the overall humidity is more in line with human physiological habits, and will not cause “air conditioning diseases” such as the dry mouth.

The refrigerant belongs to the instant-on type, and when cooling or heating is needed, it can be turned on. When the indoor temperature reaches our requirements, once it is turned off, the indoor temperature will soon approach the outdoor temperature, so “the machine can’t be turned off”. Basically, the air conditioner is always on when there are people in the room, so it is in the process of being cold or hot for a long time; the Air-source heat pumps is different.

An air-source heat pumps uses a large water system for heat exchange. When cooling or heating is needed, it can be turned on. When the indoor temperature reaches our requirements, the host system will automatically shut down. The cold water in the system is still circulating under the impetus of the circulating water pumps, and it can still maintain the internal temperature for a long time. The indoor temperature is basically the same, and it is in the preset temperature process that we need for a long time. Therefore, an air-source heat pump is more comfortable than a refrigerant air conditioner!

The air source heat pumps is connected and installed with the fan coil units, which transmits the cold heat of the air source heat pump to the room, and improves and regulates the indoor temperature as if you were in nature and enjoying the natural wind in spring.

The outlet temperature of a traditional refrigerant air conditioner is about 3 degrees in summer and higher than 60 degrees in winter, which are not acceptable to the human body, so it can’t be blown directly. The outlet temperature of the air source heat pump is about 10 degrees in summer and about 35 degrees in winter, which are all suitable temperatures, and there is no discomfort when directly blowing on the human body. Therefore, an air source heat pump is more comfortable than a traditional split air conditioner!

3. Difference in working temperature range between air source heat pump and refrigerant air conditioner:

The working temperature range of a refrigerant air conditioner is generally -7℃~43℃, which means that the refrigerant air conditioner can’t work below -7℃. In fact, split refrigerant fluorine air conditioners are difficult to heat at 0℃, and most of them use electric auxiliary heating at this time. Generally, there are electric auxiliary function keys on the remote controller of the air conditioner. Therefore, the split refrigerant fluorine air conditioner consumes electricity and has low heating capacity in winter.

However, the working range of the air source heat pump is generally -25℃~43℃, and the unit adopts enhanced vapor injection technology, which can absorb heat from the outdoor air in winter so that one power consumption can produce 3~4 heat. Therefore, the air can meet the heating demand in winter, and it is very energy-saving.

4, Maintenance difference between air source heat pump and refrigerant air conditioner:

Because the traditional air conditioner is a fluorine system, it belongs to a closed high-temperature and high-pressure system, which is troublesome to maintain; The air source heat pump central air conditioning system is an open water system, which is extremely simple to maintain.

5, Air source heat pump service life differences:

The service life of traditional split air conditioners is 7-8 years; The service life of the water system central air conditioner is longer than 15 years.

6, Economic Differences between Air Source Heat Pump and Refrigerant Air Conditioning:

When using split refrigerant fluorine air-conditioners, we need to install 300 split air-conditioners. The cooling power of a single air-conditioner is 1KW in summer and 1.5KW in winter.

When the air energy central air conditioning system is adopted, we need to install 4 sets of 130-module machines, 300 sets of indoor fan coils, and a circulating water pump with a power of 11KW.

Calculate the operating cost according to the air conditioning working time of 10 hours per day, the cooling cycle of 90 days, the heating cycle of 120 days, and the electricity of 1 yuan/kWh:

1, The total operating cost of split air conditioning refrigeration cycle operation:
1KW×450 units× 90 days× 10 hours× 1 yuan/kWh = 405,000 yuan.
Total operating cost of split air conditioning heating cycle operation:
1.5KW×450 units× 120 days× 10 hours× 1 yuan/kWh = 810,000 yuan

2,Total operating cost of refrigeration cycle of central air conditioning system:
40.2KW×6 units× 90 days× 10 hours× 0.7 (full load operation coefficient )× 1 yuan/kWh +15KW×10 hours× 90 days× 1 yuan/kWh +0.052KW×450 units× 10 hours× 90 days× 1 yuan/kWh = 151,956 yuan+13,500 yuan.

3,The total operating cost of refrigeration cycle of central air conditioning system:
3.3 kW× 6 units× 120 days× 10 hours× 0.7 (full load operation coefficient )× 1 yuan/kWh +15KW×10 hours× 120 days× 1 yuan/kWh +0.052KW×450 units× 10 hours× 120 days× 1 yuan/kWh = 218,232 yuan+18,000 yuan.

Through the above calculation, we get the following operating expenses:

From this analysis, it can be concluded that the operating cost of the split refrigerant fluorine air conditioner is more than twice that of the air energy central air conditioner, and the air energy central air conditioner saves 764,172 yuan a year compared with the traditional split air conditioner.

Therefore, adopting an air energy central air conditioning system is more energy-saving and money-saving!
To sum up, it is more reasonable to adopt an air source heat pump central air conditioning system in this project!