Screw type single-machine three-stage compression heat pump heating system and control method

Abstract

The invention discloses a screw type single-machine three-stage compression heat pump heating system and a control method. The system is characterized by comprising a single-machine three-stage screwtype compressor, and a refrigerating fluid inlet, a refrigerant outlet, a first air supplementing port, a second air supplement port and an oil return port are formed in the single-machine three-stagescrew rod type compressor. The refrigerant inlet is connected with a gas-liquid separator, and the refrigerant outlet is connected with an oil separator; the first air supplementing port is connectedwith a second economizer, and the second air supplementing port is connected with a first economizer in a cast-in mode; and an oil outlet of the oil separator is connected with an oil cooler, then the oil outlet of the oil separator is sequentially connected with an oil filter, the electromagnetic valve and an oil flow switch, finally the oil outlet of the oil separator is connected with an oil return port of a single-machine three-stage screw type compressor. The problems that an existing air source heat pump exceeds a limit value due to the compression ratio, the water outlet temperature islow, the application environment range is narrow are solved, the technical scheme can be applied to all heating areas in China, a traditional coal-fired boiler can be directly replaced, the installation and modification are convenient, the economic and rapid effects are achieved, the energy is saved, the environment is protected, and the technical scheme is a good heating technical scheme.

Description

technical field [0001] The invention relates to the technical field of air source heat pumps, in particular to a screw-type single-unit three-stage compression heat pump heating system and a control method. Background technique [0002] Among the existing heating methods in northern my country, radiator heating is the mainstream method. In recent years, under the "coal to electricity" policy, air source heat pumps combined with radiator heating have been widely used. Air source heat pumps replace coal-fired boilers for my country's environment. The improvement has played a great role, but the existing air source heat pump with radiator heating has the following defects: [0003] 1. The outlet water temperature is low, the highest is only 60°C, while the outlet water temperature of traditional coal-fired boilers is above 80°C. Due to the low water temperature, the air source heat pump cannot match the traditional cast iron radiator, so it can only be replaced with an expensive...

AI Technical Summary

Problems solved by technology

[0003] 1. The outlet water temperature is low, the highest is only 60°C, while the outlet water temperature of traditional coal-fired boilers is above 80°C. Due to the low water temperature, the air source heat pump cannot match the traditional cast iron radiator, so it can only be replaced with an expensive new radiator device, and the comfort is poor, such as the use of floor heating, the transformation workload is relatively large, and the cost is high

[0004] 2. It can only be used in areas above -25°C, and cannot be used in cold areas such as northeast and northwest, which limits the promotion of air source heat pumps

[0005] 3. Although the single-unit two-stage compressed air source heat pump or cascade air source heat pump that has been initially applied in recent years has increased the temperature of the outlet water and expanded the application range to a certain extent, because the compression ratio exceeds the limit, there are also cases in extremely cold ambient temperatures. The temperature of the output water is low, the stability and reliability of the mixed refrigerant are poor, and the energy efficiency of the unit is low.

[0006] 4. The air source heat pump starts and stops frequently during heating, the life of the unit is short, and the stability and comfort of the heating system are poor

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