Summary of the invention
Yet, the air conditioner of above-mentioned patent documentation 1 fails to supply with water as being in operation, then liquid refrigerant can not with the water heat exchange, liquid refrigerant is trapped in the heat exchanger, so, corresponding to the aperture of evaporability adjustment outdoor expansion valve, the cold-producing medium of heat exchanger outlet is controlled to be the gas of certain degree of superheat.For this reason, the flue temperature of heat exchanger outlet does not descend immediately, and only refrigerant temperature descends, and the water before protection work in the heat exchanger freezes.
In addition, the refrigerating plant of above-mentioned patent documentation 2 does not flow to the hot and cold water outlet at the occasion water that can not supply with water, so, the correct water temperature of energy measurement heat exchanger inside not, in the water occasion that the load change etc. of back air conditioner causes refrigerant temperature sharply to descend that just stopped, can not judge freezing of cold water.
The objective of the invention is to obtain such air conditioner, this air conditioner can be in running have when the occasion that disappeared of the supply of water and compressor start the occasion of supply of water out of service, prevents to freeze.
Another object of the present invention is to obtain such air conditioner, this air conditioner can not have the occasion of the supply of water not bring into operation before compressor start, prevents to freeze.
In order to address the above problem, use in refrigeration system refrigerant piping of the present invention connects off-premises station and indoor set, this off-premises station is provided with heat-exchangers of the plate type, compressor, outdoor expansion valve, and this heat-exchangers of the plate type has the plate that plate that water flows through and cold-producing medium flow through, and this indoor set is provided with indoor heat converter; It is characterized in that: the side at above-mentioned heat-exchangers of the plate type is provided with temperature sensor, the temperature of the plate that plate that flows through with the above-mentioned water of above-mentioned temperature sensor measurement and above-mentioned cold-producing medium flow through, in the value of said temperature sensor is occasion below the setting, stops the operation of above-mentioned compressor.
Preferably the said temperature sensor is arranged on such part, and this part is the gas-liquid two-phase system cryogen part of accumulating in occasion from water to above-mentioned heat-exchangers of the plate type that supply with, be the part that liquid refrigerant accumulates in occasion from water to above-mentioned heat-exchangers of the plate type that do not supply with.
In addition, the said temperature sensor preferably is located at such position, and this position more is in downside than the approximate centre of the short transverse of above-mentioned heat-exchangers of the plate type, and the above-mentioned refrigerant piping that flows into above-mentioned heat-exchangers of the plate type than cold-producing medium more is in upside.
Another use in refrigeration system refrigerant piping of the present invention connects off-premises station and indoor set, this off-premises station is provided with heat-exchangers of the plate type, compressor, outdoor expansion valve, this heat-exchangers of the plate type has the plate that plate that water flows through and cold-producing medium flow through, and this indoor set is provided with indoor heat converter; It is characterized in that: the side at above-mentioned heat-exchangers of the plate type is provided with temperature sensor, the temperature of the plate that plate that flow through with the above-mentioned water of above-mentioned temperature sensor measurement before above-mentioned compressor brings into operation and above-mentioned cold-producing medium flow through, in the value of said temperature sensor is occasion more than the setting, and above-mentioned compressor is brought into operation.
In addition, also can be provided with a plurality of above-mentioned indoor sets.
According to the present invention, side at heat-exchangers of the plate type is provided with temperature sensor, the temperature of the plate that plate that flows through with temperature sensor measurement water and cold-producing medium flow through, in the value of this temperature sensor is occasion below the setting, stop the operation of compressor, so, there is not the occasion of supply of water out of service when the supply of water becomes the occasion that do not had and compressor start in running, can prevent to freeze.
In addition, the temperature of the plate that plate that flow through with temperature sensor measurement water before the compressor starts operation and cold-producing medium flow through, in the value of temperature sensor is occasion more than the setting, make the compressor starts operation, so, before compressor start, do not have the occasion of the supply of water not bring into operation, can prevent to freeze.
The specific embodiment
Embodiments of the invention are described with reference to the accompanying drawings.
[embodiment 1]
Fig. 1 is the freeze cycle pie graph of the air conditioner 1 of present embodiment.Off- premises station 1 and 2 indoor sets 23 that air conditioner is connected as heat source unit by liquid connecting pipings 22, gas connecting pipings 21.Indoor set 23 can be 1, also can be many.Off-premises station 1 has with frequency converter running frequency is carried out the compressor 2 of the volume-variable formula of variable control, connects compressor 2 and cross valve 3.Low-pressure side at compressor 2 is provided with accumulator 6.Cross valve 3 usefulness gas refrigerant pipe arrangements 10 are connected with heat source side heat exchanger 4.Heat source side heat exchanger 4 is connected with outdoor expansion valve 5 usefulness liquid refrigerant pipe arrangements 11.
As thermal source, heat source side heat exchanger 4 uses heat-exchangers of the plate type as shown in Figure 3 to heat source unit with water.At this heat source side heat exchanger 4, by water pipe arrangement 15 from the unit the outside water of supplying with, and cold-producing medium between heat exchange.This water is adjusted in the mode that temperature and flow are in prescribed limit, carries from boiler, cold water equipment.
In addition, have high-pressure sensor 7, have low-pressure sensor 8, be provided with temperature sensor 9 in the side of heat source side heat exchanger 4 in low-pressure side in the high-pressure side of compressor 2.
At first, the process that heat source side heat exchanger 4 freezes is described.When heating, heat source side heat exchanger 4 becomes evaporimeter, and the cold-producing medium of low-temp low-pressure flows into, from the water heat absorption supplied with by external equipment and evaporate.Water is by heat absorption and temperature reduces.
As shown in Figure 2, the refrigerant temperature of heat exchanger entrance exists with ... pressure, and this pressure is identical with the low pressure of compressor substantially value.Can think that the minimum temperature of the water that heat exchanger is interior is the value identical with this refrigerant temperature.Here, make the negative pressure of refrigerant temperature change and be P1, keep P1 to control compressor frequency during operation abovely.General guard method is, in case for example low pressure is lower than P1, then reduces compressor frequency, and low pressure is returned to more than the P1.
Yet, can be the occasion that supplying temperature, flow are in the water of prescribed limit with the occasion of above-mentioned means protection.The supply of water become the occasion that do not had, become the occasion below the regulation scope of application, even compressor frequency is reduced to lower limit, low pressure also drops to and is lower than P1.As a result, it is negative that refrigerant temperature becomes, and water freezes, the heat exchanger breakage.In this occasion, need stop the operation of compressor.
Below, the freeze protection method of present embodiment is described.Fig. 3 represents heat-exchangers of the plate type 4 and figure on every side thereof.The flowing when heating of flowing of cold-producing medium.As correlation technique, there is gas refrigerant pipe arrangement 10 that temperature sensor is set at heat exchanger outlet, the value of the temperature T of having used by this temperature sensor measurement 10 is carried out the method for freeze protection.Yet, the occasion that the supply of the water that is in operation becomes and do not had, as shown in Figure 4; the supply of water become do not had in, refrigerant temperature and water temperature descend, but flue temperature T 10 does not descend immediately; descend but postpone, so, can not carry out freeze protection well.This is because as the feature of the internal structure of heat-exchangers of the plate type, top becomes gas easily, and adjusts the aperture of outdoor expansion valve corresponding to evaporability, the cold-producing medium of heat exchanger outlet is controlled to be the gas of certain degree of superheat.In the occasion that the supply of water becomes and do not had, evaporability descends, and for this reason, the aperture of outdoor expansion valve 5 diminishes, and circulating mass of refrigerant descends.Because the rate of climb of the liquid in the heat-exchangers of the plate type is suppressed, so flue temperature T 10 does not descend immediately.For this reason, in the occasion of freezing that will judge water according to the decline of flue temperature T 10, when flue temperature T 10 had just begun to descend, it is negative that refrigerant temperature has become, water generates freeze.
Therefore, in the present embodiment, the assigned position in the side of heat-exchangers of the plate type 4 is provided with temperature sensor 9, carries out freeze protection according to the temperature T of being measured by this temperature sensor 99.Heat-exchangers of the plate type 4 is overlapping which floor laminal heat exchanger of constituting by stainless steel etc., the plate of mobile plate of water and flow of refrigerant is replaced, so, side at heat-exchangers of the plate type 4, the plate that water flows and the plate of flow of refrigerant are exposed, and temperature sensor 9 is provided with contiguously with both sides' plate.Therefore, temperature sensor 9 is arranged on the face of the temperature effect that is subjected to water and cold-producing medium, measures the temperature that has reflected water and cold-producing medium both sides.When water flows, water and cold-producing medium heat exchange, T9 becomes the temperature near water.Supply as water disappears, then near the temperature of cold-producing medium, so when the supply of water had disappeared, T9 and refrigerant temperature and water temperature similarly descended.The variations in temperature of this occasion is shown in Fig. 5.In case as make T9 drop to the value of regulation, for example 2 ℃ just out of service, then the temperature of the water that temperature is higher than cold-producing medium can not become negative, can prevent freezing of sealing.
Do not stop in order not protect in the occasion that normally supplies water, only the occasion that does not have in the supply of water is more correctly protected and is stopped, and the position of the short transverse of temperature sensor 9 is described.
Fig. 6 represents the position of temperature sensor installed surface.Carried in reality under the state of heat-exchangers of the plate type 4, installed surface is the face of the vertical direction vertical with the face of refrigerant outlet ozzle 28 with there being refrigerant inlet ozzle 27.At this face, water and cold-producing medium alternately flow, and can measure the temperature that has reflected water and cold-producing medium both sides.In the present embodiment, be made as downside more, than refrigerant inlet ozzle 27 scope of upside more than the total length (H) of the short transverse of heat-exchangers of the plate type 4 half (H/2).As shown in Figure 6, be oblique line two faces partly.
Fig. 7 is divided into A~D portion with the short transverse of heat-exchangers of the plate type 4, the refrigerant condition in the expression heat exchanger.State I is the state when normally carrying out the supply of water.State I V is the state that the supply of water has stopped, the state before the water in the expression heat exchanger will begin to freeze.
A portion is the position that the state of cold-producing medium becomes gas often, near the top of heat-exchangers of the plate type 4 and refrigerant outlet ozzle 28, and air inclusion refrigerant piping 10.B portion is the position that the state of cold-producing medium becomes the gas-liquid two-phase often.C portion is that the state of cold-producing medium is two-phase in state I, becomes the position of liquid at state I V.Than heat exchanger total length H roughly half more be in the below, up to the upside of refrigerant inlet ozzle 27.D portion is the position that the state of cold-producing medium becomes liquid often, to the heat exchanger foot, comprises the liquid refrigerant pipe arrangement 11 as refrigerant inlet from the upside of refrigerant inlet ozzle 27.In the present embodiment, circulation when heating operation is described is made as refrigerant inlet ozzle 27 and refrigerant outlet ozzle 28, but when refrigerating operaton, cold-producing medium flows out from refrigerant inlet ozzle 27, and cold-producing medium flow into heat-exchangers of the plate type 4 from refrigerant outlet ozzle 28.
Heat-exchangers of the plate type is because the sectional area of flow direction is big, so the flow velocity of cold-producing medium is slack-off.Because cold-producing medium flows from bottom to top, so the liquid refrigerant in the two-phase system cryogen is difficult to rise, and separates with gas refrigerant, only liquid refrigerant is trapped in the bottom easily.In addition, because internal volume is very little, so, as the flow of refrigerant that does not evaporate comes, then heat exchanger was full of by liquid refrigerant in moment.As being full of by liquid refrigerant, then volatility further descends, and becomes to recover.For not like this, monitor the temperature of the pipe arrangement of heat exchanger outlet, for the flow of refrigerant that only allows to evaporate, the aperture of outdoor expansion valve is adjusted.In the present embodiment, utilized the feature of this heat-exchangers of the plate type.At state I V, the supply of water becomes and does not have, and can not obtain evaporability, and for this reason, the cold-producing medium that can not evaporate increases, and is trapped in the bottom of heat-exchangers of the plate type 4.Be failure to actuate as outdoor expansion valve 5, then liquid accumulates the top of heat-exchangers of the plate type 4 immediately, is filled to A portion by two-phase or liquid refrigerant, but in fact closes the control of outdoor expansion valve 5, minimizing refrigerant flow.Like this, A portion was full of by gas refrigerant in very short time, and temperature does not descend.In C portion, owing to being the gas-liquid two-phase in state I, V is full of by liquid refrigerant in state I, so temperature sharply descends.In the present embodiment, temperature sensor 9 is set in this C portion, in case it is the value of temperature sensor 9 is lower than setting, then out of service.
Below, the reason that the surface temperature of C portion under state I V sharply descends is described.
Fig. 8 represents the influence that water and cold-producing medium produce temperature sensor 9.As an example, the interior refrigerant temperature of heat exchanger of establishing state I is 1 ℃, and water temperature is 9 ℃, and the refrigerant temperature in the heat exchanger under the state I V is 0 ℃, and water temperature is 8 ℃.The surface temperature that the heat exchanger of temperature sensor 9 is set is subjected to the inner cold-producing medium and the influence of water.At first, under state I, cold-producing medium is the gas-liquid two-phase.Under the state I V that the supply of water has disappeared, cold-producing medium becomes liquid.The ratio of heat capacities two-phase system cryogen of liquid refrigerant is big.In addition, owing to water stops, so the thermal conductivity factor of water descends.Under this state, the surface temperature of heat exchanger is subjected to the Temperature Influence of refrigerant side very big, near the temperature of cold-producing medium.According to above characteristic, when C portion had disappeared in the supply of water, temperature descended significantly.
Fig. 9 represents the temperature of the A~D portion of heat-exchangers of the plate type 4 by state classification.
Determine the temperature (protection value) of the regulation of freeze protection, it is represented by dotted line.State I and II here can not protect for normally supplying with the occasion of water.
State I is a water when flowing into heat-exchangers of the plate type 4 stable, and which place of expression A~D portion all than the high temperature of protection value, does not protect to stop.
When state I I represents transition.Air conditioner is as bringing into operation or load change taking place, and then low pressure descends for the moment sometimes, descends as low pressure, and then refrigerant temperature also descends.Particularly load change takes place in the occasion of required power easily as the air conditioner of the multichamber type that is used for mansion etc.When in the present embodiment, the big occasion of load change of establishing air conditioner is transition.For measure the occasion of temperature in A~C portion, owing to supply with water, gas or two-phase system cryogen exist, and are subjected to the influence of water temperature big, so temperature does not descend a lot.Yet the cold-producing medium of D portion has liquid or mass dryness fraction is low, near the cold-producing medium of liquid, compares water temperature; the influence that is subjected to refrigerant temperature is bigger, so, dropped to the occasion of the temperature that is lower than the protection value in the temperature of cold-producing medium; even supply water is also protected to stop.
State I II and IV are the occasion that does not have the supply of water, and here needing protection stops.
State I II is illustrated in the occasion of having started under the state of not supplying with water.In this occasion, although A portion and B portion temperature descend, whether drop to protection value and uncertain, exist and do not protect the danger that stops.
The occasion that supply that state I V is illustrated in water in service has disappeared.In this occasion, as Fig. 4 and Fig. 7 explanation, the temperature of A portion does not descend substantially, and the temperature of B portion does not have decline to reach the degree of protection value yet.On the other hand, C portion and D portion are owing to be full of liquid refrigerant, and temperature sharply descends.
As seen from the above description,, do not protect when supplying with water to stop, can only when the supply of water has disappeared, correctly detecting, protect to stop it in C portion.In the present embodiment, utilize this characteristic temperature sensor 9 to be set, carry out freeze protection in C portion.Although understand and to be in half height and position of heat-exchangers of the plate type 4 and to be in the more C portion of the position of top of the refrigerant inlet ozzle 27 that flows into than liquid refrigerant, but as long as be such zone, for becoming the gas-liquid two-phase, the occasion liquid refrigerant that has disappeared in the supply of water accumulates in the occasion of supplying with water in this zone.
In the occasion of multi-room air conditioner, in the time of must considering the big transition of load change (state I I), so the suitable setting place of temperature sensor 9 is C portion as described above.Yet, for example, be difficult to become state I I in the occasion that indoor set only is 1, load change is little, so, even be D portion, can not be lower than the protection value during water flowing yet.Therefore, also can temperature sensor 9 be set in D portion.
[embodiment 2]
In addition, use the temperature sensor 9 of C portion, before the operation of compressor begins, detect whether just supplying with the water of set point of temperature scope, as be outside the prescribed limit, then do not bring into operation, thereby also can protect heat-exchangers of the plate type 4 not freezed to influence.
Figure 10 represents the flow chart of control of the freeze protection of present embodiment.At first, before compressor start, judge the water (S1) of whether just supplying with the temperature range of regulation.Temperature as water is low, is in outside the scope of application, does not then bring into operation.As in the scope of application, (S2) then brings into operation.
After just bringing into operation, in order to hold the cumulative time that has dropped to below the protection value that is used to freeze to prevent, the time started is measured (S4).Then, whether freeze, measure temperature T 9, judge whether it is lower than the i.e. protection value of value (S5) of regulation in order to judge water.The protection value for example is set at 2 ℃ etc.Be in the occasion more than the set point of temperature, time measurement is resetted (S3), the time started is measured (S4) once again, continues operation.Be in occasion below the set point of temperature at T9, whether continue continuously, judge whether the time measurement that has begun at S3 has passed through the stipulated time (S6) in order to judge its state.Like this, be in below the set point of temperature and passed through the occasion (S7) out of service of stipulated time at T9.Owing to judge that in the occasion that the temperature that is lower than the protection value has continued a period of time operation stops, for this reason, occasion of having surveyed at flase drop or the occasion that exists unexpected refrigerant temperature to descend are for the moment also protected and are stopped even can preventing from just to supply with water.