Operation control method of two-stage compression heat pump system and heat pump system

Abstract

The invention discloses a running control method of a double-stage compression heat pump system and a heat pump system, and aims at providing a method and a system for balancing and coordinating lubricating oil between high pressure stage and low pressure stage as well as realizing uniform power consumption of each compressor in running. The method comprises the steps of changing output points ofa high pressure stage compressor set and a low pressure stage compressor set in order to enable the high pressure stage compressor set to run as the low pressure stage compressor set and enable the low pressure stage compressor set to run as the high pressure stage compressor set when the single running time t of the compressor sets is beyond the alternative running time cycle T; starting compressor sets based on the principle of high and low pressure stage compressor launching ratio m and the principle of firstly starting the compressor with the minimum running time; adding 1 to the running time corresponding to the started compressor; synchronously clearing the single running time of the compressor sets in previous running cycle; starting to record the single running time of the compressor set in the current cycle; and starting new running cycle. According to the method and the system, the power consumption of each compressor in running is uniform; the system reliability is high; theoil retuning uniformity is realized.

Description

technical field [0001] The invention relates to the technical field of heat pumps, and more specifically relates to an operation control method of a two-stage compression heat pump system and the heat pump system. Background technique [0002] In the heat pump system, the compressor is an important part of the system performance. When the two-stage compression heat pump system is running, the high-pressure compressor unit and the low-pressure compressor unit are connected in series. Because the pressure range and temperature range of the high-low pressure compressor unit are different. Similarly, the low-pressure stage works in a low-temperature and low-pressure environment for a long time, and the high-pressure stage works in a high-temperature and high-pressure environment for a long time. With the accumulation of running time, some parts of the compressors in the high- and low-pressure stage compressor units wear unevenly. For a two-stage compression heat pump system, the...

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Problems solved by technology

The higher the pressure, the more dissolved lubricating oil. In the two-stage compression heat pump system, the low-pressure stage compressor works in the low-pressure and low-temperature range for a long time, and the high-pressure stage compressor works in the high-temperature range for a long time. The amount of lubricating oil dissolved is different. The phenomenon of uneven oil return in the high and low pressure stages of the compressor occurs, that is, the low pressure stage compressor has more oil, which affects the performance of the compressor, and the high pressure stage compressor lacks oil, and the cylinder body is severely worn, the power consumption increases sharply, and the noise increases. The sealing becomes weak, or even a severe lack of oil will cause the cylinder of the compressor to be pulled, the compressor will be damaged, and the worn slag will enter the refrigerant, flow into the indoor unit and form a liquid film on the surface of the outdoor unit, which will affect the heat exchange and flow into the refrigerant. The throttling valve will clog the pipes and eventually reduce the efficiency of the heat pump system

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