A constant power output refrigeration and heating device

Abstract

The invention discloses a constant power output refrigeration and heating device, comprising a compressor, a condenser, a drying filter, a main evaporator electronic expansion valve, a main evaporator, an electric heater, a flow meter, a water tank, a liquid level meter, and a circulation pump. The compressor is connected to the condenser and the main evaporator, the condenser is connected to the drying filter, the drying filter is connected to the main evaporator electronic expansion valve, the main evaporator electronic expansion valve is connected to the inlet of the main evaporator, the outlet of the main evaporator is connected to the electric heater, the inlet of the main evaporator is connected to the circulation pump, the circulation pump is connected to the water tank, the water tank is connected to the electric heater, and the water tank is connected to the liquid level meter. The invention can achieve constant output of refrigeration power without frequency conversion and electric heater for thermal confrontation, and the whole machine has high stability and low energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of new energy testing, such as battery pack testing, and specifically to a constant power output refrigeration and heating device. Background Art

[0002] In the current refrigeration and heating devices, the control of the unit usually adopts the temperature control method to control the outlet temperature or the user uses the temperature measurement. For applications in certain fields, it is necessary to provide a constant cooling capacity or heat output for testing or production process requirements. For constant power output control, the industry currently adopts frequency conversion control technology and a combination of large and small compressors to achieve it. However, frequency conversion technology is often difficult to implement in some complex working conditions, such as low temperature conditions. Since the compressor itself has a low evaporation pressure, if it works at a low frequency for a long time, it will cause poor oil return, thereby causing damage to the compressor. In the form of a combination of large and small compressors, the cooling capacity is divided into three intervals: high, medium and low. The high zone uses dual compressors to work together to provide cooling capacity, the middle zone uses a large compressor to work alone, and the low zone uses a small compressor to work alone. No matter in which temperature zone, if you want to control the output of cooling capacity, you need the heater to participate in thermal confrontation to achieve it, which consumes a lot of power and the overall energy consumption of the equipment is high. Summary of the invention

[0003] The present invention provides a constant power output refrigeration and heating device, the purpose of which is to overcome the above-mentioned shortcomings of the prior art and provide a device that can achieve constant output of refrigeration power without frequency conversion and electric heater for thermal resistance, and the whole machine has higher stability and lower energy consumption.

[0004] The technical solution adopted by the present invention is:

[0005] The invention discloses a constant power output refrigeration and heating device, comprising a compressor, a condenser, a drying filter, a main evaporator electronic expansion valve, a main evaporator, an electric heater, a flow meter, a water tank, a liquid level meter, and a circulation pump. The compressor is connected with the condenser and the main evaporator, the condenser is connected with the drying filter, the drying filter is connected with the main evaporator electronic expansion valve, the main evaporator electronic expansion valve is connected with the inlet of the main evaporator, the outlet of the main evaporator is connected with the electric heater, the inlet of the main evaporator is connected with the circulation pump, the circulation pump is connected with the water tank, the water tank is connected with the electric heater, and the water tank is connected with the liquid level meter.

[0006] Furthermore, it also includes an auxiliary evaporator and an auxiliary evaporator electronic expansion valve. The auxiliary evaporator is connected to the compressor, and the auxiliary evaporator electronic expansion valve is connected to the auxiliary evaporator and the drying filter.

[0007] Furthermore, an outlet temperature sensor is provided at the rear end of the electric heater.

[0008] Furthermore, a return temperature sensor is provided at the flow meter.

[0009] Furthermore, it also includes a PID temperature adjustment module, which is connected to the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve.

[0010] Furthermore, the battery pack temperature is set to t1, the medium outlet temperature is set to t2, the medium return temperature is set to t3, and Δt is a theoretical temperature difference value calculated based on the input cooling capacity.

[0011] Furthermore, the control logic of the cooling constant power mode t2 is:

[0012] If t3-t2>Δt, then increase the t2 value;

[0013] If t3-t2=Δt, the value of t2 remains unchanged;

[0014] If t3-t2<Δt, the t2 value decreases;

[0015] The t2 value uses a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 adjustment method is as follows:

[0016] The way to reduce t2 is: increase the opening of the electronic expansion valve of the main evaporator and reduce the opening of the electronic expansion valve of the auxiliary evaporator;

[0017] The way to increase t2 is: reduce the opening of the electronic expansion valve of the main evaporator and increase the opening of the electronic expansion valve of the auxiliary evaporator;

[0018] The opening adjustment of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve is achieved by adjusting the fan speeds of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve.

[0019] Furthermore, the control logic of the heating constant power mode t2 is:

[0020] If t2-t3>Δt, reduce the t2 value;

[0021] If t2-t3=Δt, the value of t2 remains unchanged;

[0022] If t2-t3<Δt, then increase the t2 value;

[0023] The t2 value adopts a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 value is adjusted by adjusting the output power of the electric heater.

[0024] The beneficial effects of the present invention are:

[0025] 1. Reduce the power of the whole machine and lower the operating energy consumption;

[0026] 2. The control logic algorithm is more reasonable to ensure control accuracy;

[0027] 3. The controllable range of cooling capacity is wider, and the normal operation of the unit can be guaranteed even under severe low and high temperature conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0029] Figure 1 It is a schematic diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0031] As shown in the figure, the present invention discloses a constant power output refrigeration and heating device, including a compressor 1, a condenser 2, a drying filter 3, a main evaporator electronic expansion valve 4, a main evaporator 5, an electric heater 6, a flow meter 7, a water tank 8, a liquid level meter 9, and a circulating pump 10. The compressor 1 is connected to the condenser 2 and the main evaporator 5, the condenser 2 is connected to the drying filter 3, the drying filter 3 is connected to the main evaporator electronic expansion valve 4, the main evaporator electronic expansion valve 4 is connected to the inlet of the main evaporator 5, the outlet of the main evaporator 5 is connected to the electric heater 6, the inlet of the main evaporator 5 is connected to the circulating pump 10, the circulating pump 10 is connected to the water tank 8, the water tank 8 is connected to the electric heater 6, and the water tank 8 is connected with a liquid level meter 9.

[0032] In one embodiment of the present invention, an auxiliary evaporator 11 and an auxiliary evaporator electronic expansion valve 12 are further included. The auxiliary evaporator 11 is connected to the compressor 1 , and the auxiliary evaporator electronic expansion valve 12 is connected to the auxiliary evaporator 11 and the drying filter 3 .

[0033] Refrigeration constant power output process: the circulating pump 10 is turned on and runs for 20 seconds, and then the compressor 1 and the condensing fan 2 are turned on. According to the heat calculation formula Q=C*m*Δt, it can be known that under the premise that the flow rate and specific heat are quantitative, the size of the cooling capacity depends on the temperature difference, that is, the control of the output size of the cooling capacity can be achieved by controlling the temperature difference between the inlet and outlet of the medium. The control of the temperature difference can be converted into the control of the medium outlet temperature, so that the control of the cooling capacity can actually be directly converted into the control of the temperature. Because the greater the difference between the medium outlet temperature and the battery pack, the greater the corresponding medium inlet and outlet temperature difference will be, and vice versa, the smaller the difference, the smaller the corresponding medium inlet and outlet temperature difference will be. According to this rule, it is possible to realize how to control the medium outlet temperature from the control logic.

[0034] In one embodiment of the present invention, an outlet temperature sensor 13 is provided at the rear end of the electric heater 6. The outlet temperature sensor 13 is used to detect the temperature at the outlet of the medium.

[0035] In one embodiment of the present invention, a return temperature sensor 14 is provided at the flow meter 9. The return temperature sensor is used to detect the temperature at the medium inlet.

[0036] In one embodiment of the present invention, a PID temperature adjustment module is further included, and the PID temperature adjustment module is connected to the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve.

[0037] In one embodiment of the present invention, the battery pack temperature is set to t1, the medium outlet temperature is set to t2, the medium return temperature is set to t3, and Δt is a theoretical temperature difference value calculated according to the input cooling capacity.

[0038] In one embodiment of the present invention, the control logic of the cooling constant power mode t2 is:

[0039] If t3-t2>Δt, then increase the t2 value;

[0040] If t3-t2=Δt, the value of t2 remains unchanged;

[0041] If t3-t2<Δt, the t2 value decreases;

[0042] The t2 value uses a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 adjustment method is as follows:

[0043] The way to reduce t2 is: increase the opening of the electronic expansion valve of the main evaporator and reduce the opening of the electronic expansion valve of the auxiliary evaporator;

[0044] The way to increase t2 is: reduce the opening of the electronic expansion valve of the main evaporator and increase the opening of the electronic expansion valve of the auxiliary evaporator;

[0045] The opening adjustment of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve is achieved by adjusting the fan speeds of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve.

[0046] In one embodiment of the present invention, the control logic of the heating constant power mode t2 is:

[0047] If t2-t3>Δt, reduce the t2 value;

[0048] If t2-t3=Δt, the value of t2 remains unchanged;

[0049] If t2-t3<Δt, then increase the t2 value;

[0050] The t2 value adopts a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 value is adjusted by adjusting the output power of the electric heater.

[0051] The control logic algorithm of the present invention is reasonable and the control accuracy is guaranteed.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A constant power output refrigeration and heating device, characterized in that: It includes a compressor, a condenser, a filter drier, an electronic expansion valve for a main evaporator, a main evaporator, an electric heater, a flow meter, a water tank, a liquid level meter, and a circulating pump. The compressor is connected to the condenser and the main evaporator, the condenser is connected to the filter drier, the filter drier is connected to the electronic expansion valve for the main evaporator, the electronic expansion valve for the main evaporator is connected to the inlet of the main evaporator, the outlet of the main evaporator is connected to the electric heater, the inlet of the main evaporator is connected to the circulating pump, the circulating pump is connected to the water tank, the water tank is connected to the electric heater, a liquid level meter is connected to the water tank, an auxiliary evaporator and an electronic expansion valve for the auxiliary evaporator are also included, the auxiliary evaporator is connected to the compressor, the electronic expansion valve for the auxiliary evaporator is connected to the auxiliary evaporator and the filter drier, an outlet temperature sensor is provided at the rear end of the electric heater, a return temperature sensor is provided at the flow meter, and a PID temperature adjustment module is also included, the PID temperature adjustment module is connected to the electronic expansion valve for the main evaporator and the electronic expansion valve for the auxiliary evaporator, the battery pack temperature is set to t1, the medium outlet temperature is set to t2, the medium return temperature is set to t3, Δt is the theoretical temperature difference calculated based on the input cooling capacity, and the control logic of the cooling constant power mode t2 is: If t3-t2>Δt, then increase the t2 value; If t3-t2=Δt, the value of t2 remains unchanged; If t3-t2<Δt, the t2 value decreases; The t2 value uses a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 adjustment method is as follows: The way to reduce t2 is: increase the opening of the electronic expansion valve of the main evaporator and reduce the opening of the electronic expansion valve of the auxiliary evaporator; The way to increase t2 is: reduce the opening of the electronic expansion valve of the main evaporator and increase the opening of the electronic expansion valve of the auxiliary evaporator; The opening adjustment of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve is achieved by adjusting the fan speeds of the main evaporator electronic expansion valve and the auxiliary evaporator electronic expansion valve.

2. A constant power output refrigeration and heating device according to claim 1, characterized in that: The control logic of heating constant power mode t2 is: If t2-t3>Δt, reduce the t2 value; If t2-t3=Δt, the value of t2 remains unchanged; If t2-t3<Δt, then increase the t2 value; The t2 value adopts a PID temperature adjustment module, which is automatically adjusted according to the difference between the actual temperature difference and the theoretical temperature difference Δt. The t2 value is adjusted by adjusting the output power of the electric heater.

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