JPS59109748A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner, particularly to its refrigerant control.

Conventionally, in the refrigerant control of air conditioners, it is common to use capillary tubes or thermostatic expansion valves.
Different design conditions will not necessarily result in optimal operation. In addition, in the case of a thermostatic expansion valve, refrigerant control is performed to keep the superheat (hereinafter referred to as SR) of the suction refrigerant constant, but keeping SH constant is not necessarily optimal control. No. The optimal control here means protecting the refrigerant circuit by not performing liquid backup operation under a wide range of operating conditions, keeping the discharge pressure (high pressure) below a certain value, or keeping the discharge refrigerant temperature below a certain value. In addition to satisfying the minimum requirements above, control or energy consumption efficiency (EER =
This refers to control that maximizes the performance (noh or kukata).

The present invention has been made in consideration of the above, and it is an object of the present invention to provide an air conditioner that enables optimal control of refrigerant, which was not possible with conventional capillary tube systems or thermostatic expansion valve systems. purpose.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 5 is a compressor, and the compressor 5 has a condenser 6.
, the expansion valve 7 and the evaporator 8 are sequentially connected via piping to constitute a normal refrigeration cycle (refrigerant circuit). Further, a pressure sensor 10a is provided in the discharge pipe 2 (sieve pressure part) of the compressor 5, a temperature sensor 11a is provided in the outlet pipe 3 of the condenser 6, and a pressure sensor 10a is provided in the suction pipe 1 (low pressure part) of the compressor 5. A sensor 10b and a temperature sensor llb are provided, and each sensor 10
a.

10b, lla, llb output signals to the controller 9,
The expansion valve 7 is controlled by the signal from the controller 9. 4 indicates an inlet pipe of the evaporator 8.

Further, FIG. 2 shows a Mollier diagram, and states 1 to 4 correspond to pipes 1 to 4 in FIG. 1. Pressure P in state 1,
is measured by the pressure sensor 10b, and the enthalpy 1
1 is calculated from the temperature T1 and pressure P1 measured by the temperature sensor llb.

Since the pressure in state 3 is the same as the pressure P in state 2, it is measured by the pressure sensor 10a, and the enthalpy i3 is equal to the temperature T3 measured by the temperature sensor lla.
and pressure P2. Therefore, enthalpy 1. ．． 1. is expressed by the following equation.

L= f+ (Pr TI ) is= f2 (P2 t Ts ) In addition, once the suction refrigerant temperature T2, suction pressure PI, and discharge pressure P are determined, the compressor 5 calculates the refrigerant circulation amount G and input W.
can be calculated. Therefore, G and W are expressed by the following equations.

G=fsCPs, P2. TI) W=f4(PI, Pl, TI) Furthermore, from the above four equations, the capacity Q and energy consumption efficiency EEE of the wall air conditioner can be determined by the following equation.

Q=GX (t, -12) EER=Q/W These calculations are performed by the controller 9, and the controller 9 applies a drive signal to the expansion valve 7 based on the calculation results.

Next, there are many algorithms that can be considered to optimally control an air conditioner with these control functions, but as a typical control method, when there is a large difference between the room temperature in the room where the walls are controlled and the set temperature, the capacity is maximized. There is a method of controlling σ1j such that the EER becomes maximum when the room temperature approaches the set temperature.

An example of an algorithm for controlling operation to maximize EER will be explained with reference to the flowchart in FIG. First, when starting operation, set SR = 2deg, and set the temperature of each part to K.
Measure Tt, Ts, pressure R, and Pt, and calculate EER. Next, change SH to 4 deg and 6 deg, and each 1! ;Calculate ER and determine SH with the maximum EER. At this time, 2 in the range of 2 to 6 degrees
Approximate with the following curve to determine SR. And decided S
Drive on H. Also, after a certain period of time such as 30 minutes or 1 hour has passed, taking into account changes in the outside temperature, the system returns to the initial settings, determines the optimum SH again, and continues operation.

Note that the algorithm shown in FIG. 3 is just an example, and the controller 9
It is also possible to directly determine the optimum SH from the initial setting operating state of the SH by providing an advanced calculation function to the SH. Of course, it is also possible to control so that the ability Q is maximized. It is also possible to provide temperature sensors in the condenser 6 and evaporator 8 in place of the pressure sensors 10a and 10b to measure the condensation temperature and the temperature at which the rice cake rises, and calculate the pressure from these temperatures.

As described above, in the present invention, the pressures in the high pressure section and the low pressure section of the refrigerant circuit are detected by the pressure detection means, and the temperature at the outlet side of the condenser and the temperature at the suction side of the compressor are respectively detected by the temperature detection means. However, in response to the detection signals of these detection means, the controller calculates the capacity and energy consumption efficiency of the air conditioner, and the valve mechanism is controlled based on the calculation results. By achieving optimal refrigerant control for air conditioners, which was previously impossible to achieve, this can be achieved.

Note that the present invention can also be effectively applied to an air conditioner in which the capacity of the compressor is variable using an inverter.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an air conditioner according to the present invention, Fig. 2 is a diagram showing the characteristics of the air conditioner according to the present invention;
The figure is a flowchart showing an example of the algorithm of the air conditioner according to the present invention. 1... Suction piping, 2... Discharge piping, 3... Condenser outlet piping, 4... Evaporator inlet piping, 5... Compressor,
6... Condenser, 7... Expansion valve, 8... Evaporator, 9
...controller, 10a, 10b=-pressure sensor, 11a, 1lb - temperature sensor. Agent Makoto Kuzuno - No. 1 itg KCQI/Ni 9 Fig. 3 46sH

Claims (4)

[Claims] (1) A refrigerant circuit in which the compressor, condenser, and evaporator are connected by piping, pressure detection means for detecting the pressure in the high pressure part and low pressure part of the refrigerant circuit, and the temperature on the outlet side of the condenser and the pressure of the compressor. temperature detection means for respectively detecting the suction side temperature;
An air conditioner comprising: a valve mechanism inserted into a refrigerant circuit; and a controller that controls an expansion valve in response to output signals from each pressure detection means and each temperature detection means. (2) The air conditioner according to claim 1, wherein the controller controls the valve mechanism so that the capacity of the air conditioner is maximized. (3) The air conditioner according to claim 1, wherein the controller controls the valve mechanism so that energy consumption efficiency is maximized. (4) The air conditioner according to any one of claims 1 to 3, wherein each pressure detection means is a pressure sensor that directly detects the pressure in the high pressure section and the low pressure section, respectively. . (A patent characterized in that each pressure detection means is a temperature sensor that indirectly detects the pressure in the high pressure section and the low pressure section by detecting the condensation temperature of the condenser and the evaporation temperature of the evaporator, respectively. An air conditioner according to any one of claims 1 to 3.