CN100422661C

CN100422661C - Heat pump

Info

Publication number: CN100422661C
Application number: CNB2005800165836A
Authority: CN
Inventors: 本间雅也; 药丸雄一; 田村朋一郎; 斋藤哲哉
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2004-12-09
Filing date: 2005-12-09
Publication date: 2008-10-01
Anticipated expiration: 2025-12-09
Also published as: US20070068178A1; JP3929067B2; JPWO2006062190A1; WO2006062190A1; CN1957213A

Abstract

A heat pump of the present invention has a compressor and an expander coupled with a common axis of rotation, a first throttling device disposed in a circulation passage of refrigerant, and a second throttling device disposed in a bypass passage diverted from the expander. A control device controls the openings of these throttling devices. The control device executes a first controlling in which the opening of the first throttling device is adjusted in order to bring a high pressure PH in a refrigeration cycle close to a predetermined value determined based on a value at which the coefficient of performance (COP) of the heat pump is optimized, and after the first controlling is completed, it executes a second controlling in which the opening of the second throttling device is adjusted in order to bring a degree of superheat SH close to a predetermined positive value. This ensures smooth and stable operations of the heat pump.

Description

Heat pump

Technical field

The present invention relates to as air conditioner, hot-warer supplying machine etc. and useful heat pump, in more detail, relate to and possess the heat pump that utilizes the mechanism that decompressor recovers energy.

Background technology

Used in the heat pump of decompressor replacing expansion valve, can reclaim the energy that cold-producing medium expands as electric power or power.Usually use positive-displacement expansion engine as decompressor, described positive-displacement expansion engine has the space that is used to the volume-variable that imports cold-producing medium and make its expansion.With regard to the energy that utilizes decompressor to carry out reclaims, using carbon dioxide and high-pressure side to reach striding in the critical cycle of supercriticality as cold-producing medium, its meaning is especially great.

With regard to decompressor, if on its structure cold-producing medium not along the regulation direction by then recovering energy.But, in the heat pump that uses as air conditioner, use as evaporimeter during as radiator, at cooling operation when the warm running of system owing to needing to be disposed at indoor heat exchanger, therefore when cooling operation and the warm running of system, need make the cold-producing medium counter current basically.

Disclose for TOHKEMY 2001-66006 number and can the both sides when cooling operation and the warm running of system utilize decompressor to carry out the heat pump that energy reclaims.This heat pump is designed to the switching by cross valve, when arbitrary running that refrigeration, system warm up, cold-producing medium is flowed in decompressor along same direction.In addition, in this heat pump, in order will intactly to be consumed in the running of compressor by the energy that decompressor reclaims, decompressor and compressor are connected promptly with same rotating shaft and directly link.

In the heat pump that has directly linked decompressor and compressor, because decompressor and compressor with identical rotary speed work, therefore can't make the discharge capacity of decompressor and compressor than changing corresponding to operating condition.That is, this kind heat pump has density than certain restriction.Therefore, though it is superior on the organic efficiency of energy directly to have linked the heat pump of decompressor and compressor, but be difficult to carry out level and smooth running corresponding to operating condition.Disclose for TOHKEMY 2003-121018 number and relaxed this difficult heat pump.

As shown in figure 14, TOHKEMY 2003-121018 number, with TOHKEMY 2001-66006 number same, the heat pump of following design is disclosed, promptly at 2 cross valves 151,153 of body 111 configurations, by the switching of cross valve 151,153, when arbitrary running that refrigeration, system warm up, make cold-producing medium along same direction in decompressor 103 and compressor 101 mobile (with reference to this communique Fig. 4).In the air conditioner that has used this heat pump, when system is warm, the path that selection is represented by solid line in cross valve 151,153, indoor heat converter 152 is brought into play function as radiator, and outdoor heat converter 154 is brought into play function as evaporimeter.In this air conditioner, when refrigeration, the path that selection is illustrated by the broken lines in cross valve 151,153, indoor heat converter 152 is brought into play function as evaporimeter, and outdoor heat converter 154 is brought into play function as radiator.In this heat pump, decompressor 103 and compressor 101 directly link and have a rotating shaft, and this rotating shaft is driven by motor 105.

In TOHKEMY 2003-121018 number disclosed heat pump, on the bypass circulation 112 that disposes in parallel with decompressor 103, dispose expansion valve (by-passing valve) 107, and then also in series dispose expansion valve 106 with decompressor 103.And, corresponding to operating condition, the aperture of control expansion valve 106 or expansion valve 107.Accumulator tank 100 prevents that by temporarily storing cold-producing medium cold-producing medium is too much to the inflow of decompressor 103.

As mentioned above, the heat pump that has directly linked decompressor and compressor is superior on the recovery this point of energy, but can't make the discharge capacity of decompressor and compressor than changing corresponding to operating condition.For example, if the standard conditions during with cooling operation are the reference design decompressor, then the relative required value of discharge capacity of decompressor is excessive during the warm running of system.Therefore, in TOHKEMY 2003-121018 number disclosed heat pump, when the warm running of system, expansion valve 107 full cut-offs are suitably controlled the aperture of expansion valve 106.On the other hand, when cooling operation, the discharge capacity of decompressor 103 is littler than required value sometimes.Under this situation, expansion valve 106 standard-sized sheets are suitably controlled the aperture of expansion valve 107.

So, TOHKEMY 2003-121018 number disclosed heat pump is by adjusting the opposing party's aperture under the state of side's standard-sized sheet that makes expansion valve 106,107 or full cut-off, can avoid density than certain restriction, carry out level and smooth do action corresponding to operating condition.

Figure 15 is a mollier diagram of representing the freeze cycle of heat pump as shown in figure 14, and transverse axis H represents enthalpy, and longitudinal axis P represents pressure.The indoor heat converter 152 of bringing into play function as radiator or outdoor heat converter 154, dispel the heat and arrive state b from the cold-producing medium of the state a that is in high pressure P H of compressor 101 ejection.Cold-producing medium arrives state c by expansion valve 106 isenthalpic expansions, so in decompressor 103 isenthalpic expansion and arrive the state d of low pressure PL.Cold-producing medium absorbs heat in the outdoor heat converter 154 of bringing into play function as the politics and law device or indoor heat converter 152 and surpasses with the intersection point (state e) of saturated vapor line behind the state f of arrival as the superheated vapor state, flows into once more in the compressor 101.In this heat pump, utilize the enthalpy difference W of decompressor 103 recovery and state c and state d ₂Suitable energy.Therefore, in this heat pump basically as long as compressor 101 is dropped into and enthalpy difference W from state a and state f ₁Deduct enthalpy difference W ₂And the value (W that obtains ₁-W ₂) suitable power gets final product.

As mentioned above, in TOHKEMY 2003-121018 number disclosed heat pump, if the discharge capacity of decompressor 103 is littler than required value, then open expansion valve 107, the part of cold-producing medium flows in bypass circulation 112.But, flow increase along with the cold-producing medium that in bypass circulation 112, flows, the high side pressure PH of freeze cycle and the difference of low-pressure lateral pressure PL reduce, and follow in this, and the degree (degree of superheat) that flows into overheated (superheat) of the cold-producing medium in the compressor 101 also reduces.

This variation is represented in the lump by Figure 15.If the aperture of expansion valve 107 increases, then (a～f) shifts to freeze cycle (a '～f ') freeze cycle.As shown in figure 15, be accompanied by this transfer, high side pressure is reduced to PH ' from PH, and low-pressure lateral pressure rises to PL ' from PL.And the state f of the size of the degree of superheat of expression cold-producing medium and the enthalpy difference of state e are reduced to SH ' from SH.

If the degree of superheat SH of cold-producing medium reduces, then be difficult to guarantee the reliability of compressor 101 and be difficult to carry out stable running.If degree of superheat SH is too small, then the part of cold-producing medium flows in the compressor 101 under the state that keeps liquid, thus the trouble that has the hydraulic pressure that in compressor 101, carries out avoiding to contract.

In addition, in TOHKEMY 2003-121018 number disclosed control, in order to ensure level and smooth running, and the aperture of adjustment expansion valve 106,107, as its result, high side pressure PH change.But, because the high side pressure PH of freeze cycle is to efficiency factor (the coefficient ofperformance of heat pump; Therefore COP) bring influence,, and consider also preferably suitably to carry out the control of expansion valve from the viewpoint of raising the efficiency coefficient not only from guaranteeing the viewpoint of level and smooth running.

Also have, efficiency factor (COP) is to represent that the energy that obtains drops into the nondimensional numerical value of the ratio of the energy in the heat pump relatively.

Summary of the invention

The objective of the invention is in the heat pump that has directly linked decompressor and compressor, guarantee the reliability of compressor, and can carry out the good running of efficient.

Heat pump of the present invention has: compressor; Radiator; Decompressor; Evaporimeter; Body, it forms cold-producing medium in order via described compressor, described radiator, described decompressor, and described evaporimeter and the circulating path that circulates, and the bypass path that do not flow to described evaporimeter from described radiator via described decompressor of cold-producing medium; The first throttle device, it is disposed between described radiator and the described decompressor or on the described circulating path between described decompressor and the described evaporimeter, and aperture is variable; Second throttling arrangement, it is disposed on the described bypass path, and aperture is variable; Control device, it adjusts the aperture of described first throttle device and the aperture of described second throttling arrangement.In this heat pump, described compressor and described decompressor are connected with identical rotating shaft.

And then in heat pump of the present invention, described control device is implemented first control, and described first control reaches optimum value and definite setting PH as the high side pressure PH of the cold-producing medium that circulates with based on the efficiency factor of heat pump in described circulating path _TDifference not at prescribed limit PH _DRWhen interior, the aperture that changes described second throttling arrangement makes described pressure P H and described setting PH _TThe absolute value of difference diminish.And, finish the back in described first control and implement second control, described second implements control as the degree of superheat SH of the cold-producing medium that flows into described compressor with as the setting SH of predetermined positive value _TDifference not at prescribed limit SH _DRWhen interior, the aperture that changes described first throttle device makes the described degree of superheat and described setting SH _TThe absolute value of difference diminish.

In the present invention, adjust second throttling arrangement, when guaranteeing level and smooth do action and raising the efficiency coefficient, continuing to adjust the first throttle device, the degree of superheat of control cold-producing medium.By this control, in the heat pump that has directly linked compressor and decompressor, can guarantee the reliability of compressor, and carry out corresponding to the level and smooth of operating condition and effectively running.

Description of drawings

Fig. 1 is the figure of an example of the structure of expression heat pump of the present invention;

Fig. 2 is the figure of another example of the structure of expression heat pump of the present invention;

Fig. 3 is the flow chart of an example of the control implemented of expression control device;

Fig. 4 is the figure of the relation of the ejection refrigerant pressure Pd that represents outside air temperature T and compressor of the ejection refrigerant temperature Td by compressor;

Fig. 5 is another routine flow chart of the control implemented of expression control device;

Fig. 6 is the mollier diagram of the variation of the illustration freeze cycle that is accompanied by the control that control device implements;

Fig. 7 is the figure of another example of the structure of expression heat pump of the present invention;

Fig. 8 is the figure of another example of the structure of expression heat pump of the present invention;

Fig. 9 is the figure of another example of the structure of expression heat pump of the present invention;

Figure 10 is the figure of another example of the structure of expression heat pump of the present invention;

Figure 11 is the example of structure that expression possesses the heat pump of the present invention of cross valve;

Figure 12 is the figure of relation of the temperature of the position of expression cold-producing medium when having used fluorine Lyons as cold-producing medium, radiator and cold-producing medium;

Figure 13 is the figure of relation of the temperature of the position of expression cold-producing medium when having used carbon dioxide as cold-producing medium, radiator and cold-producing medium;

Figure 14 represents the figure of the structure of existing heat pump;

Figure 15 is the mollier diagram of the variation of the expression cold-producing medium circulation that is accompanied by the control of implementing in existing heat pump.

The specific embodiment

Below, with reference to description of drawings preferred implementation of the present invention.Also have, in the following description, to identical parts or the identical symbol of step mark, the repetitive description thereof will be omitted.

Fig. 1 represents the structure of a mode of heat pump of the present invention.Heat pump 71 possesses compressor 1, radiator 2, decompressor 3, evaporimeter 4 as the primary structure unit of the basic function that is used to bring into play heat pump.These primary structure unit connect by body 11, and described body 11 forms cold-producing mediums in order via compressor 1, radiator 2, decompressor 3, and evaporimeter 4 and the circulating path of circulation.One end of body 12 is connected with body 11 between radiator 2 and the decompressor 3, and its other end is connected with body 11 between expansion valve 3 and the evaporimeter 4.Body 12 has formed the bypass path that cold-producing medium does not flow to evaporimeter 4 from radiator 2 via decompressor 3.

Cold-producing medium circulates along the direction shown in the arrow of Fig. 1, and is released in the heat that absorbs in the evaporimeter 4 in radiator 2.Thus, this system as from evaporimeter 4 to the heat pump of radiator 2 extract heat and bring into play function.Compressor 1 and decompressor 3 are connected with a rotating shaft (axle) 10.Compressor 1 is worked by power of giving from the motor 5 that is connected with axle 10 and the power that utilizes decompressor 3 to reclaim.Directly linked compressor 1 and decompressor 3 and with the heat pump of identical rotating speed rotation owing to can't control the rotating speed of decompressor 3 independently by the rotating speed of compressor 1, therefore be subjected to so-called density than certain restriction.For fear of this restriction, and in heat pump 71, body 12 has formed the bypass circulation of cold-producing medium, and disposes expansion valve 7 on this bypass circulation.

In heat pump 71, between radiator 2 and decompressor 3, dispose first expansion valve 6 as the first throttle device, on bypass circulation, dispose second expansion valve 7 as second throttling arrangement.If be conceived to express with the relation of decompressor 3, then first expansion valve 6 in series disposes with decompressor 3, and second expansion valve 7 disposes in parallel with decompressor 3.The aperture of

expansion valve

6,7 can be utilized control device (controller) 30 controls.If utilize controller 30 that the aperture of second expansion valve 7 is set at minimum (that is, becoming full-shut position), then Xun Huan cold-producing medium does not flow in bypass circulation, and all flows in the decompressor 3.

In heat pump 71, between evaporimeter 4 and compressor 1, dispose the temperature sensor (first temperature testing organization) 23 that the temperature that flows into the cold-producing medium in the compressor 1 is measured, on evaporimeter 4, dispose the temperature sensor (second temperature testing organization) 24 that the temperature to the cold-producing medium of evaporimeter 4 detects.If the temperature (refrigerant evaporator temperature) of the temperature of the cold-producing medium in can specific inflow compressor 1 and cold-producing medium evaporation in evaporimeter, then can calculate the degree of superheat SH of this cold-producing medium.So, second temperature testing organization of the temperature of first temperature testing organization that heat pump detects the temperature that flows into the cold-producing medium in the compressor for specific degree of superheat SH can also have and the cold-producing medium that detects evaporimeter.

In heat pump 71, also dispose the temperature sensor 25 of measuring outside air temperature T.As described later, if outside air temperature T uprises, the necessity that then increases the aperture of second expansion valve 7 uprises.So heat pump can also have the 3rd temperature testing organization of the outer temperature of detection system." temperature outside the system " specifically is meant in the inflow radiator 2 and the temperature of heated medium, for example temperature of the water of the temperature of outer gas or inflow.

In heat pump 71, between compressor 1 and radiator 2, dispose the pressure sensor 21 of mensuration from the pressure P d of the cold-producing medium of compressor 1 ejection.The high side pressure PH of pressure P d and freeze cycle is suitable.So heat pump also can have the pressure detecting mechanism of detection from the pressure of the cold-producing medium of compressor ejection for specified pressure PH.

The high side pressure PH of freeze cycle also can be calculated by the measured value beyond the pressure P d.For example, can measure outside air temperature T and, calculate pressure P H by these temperature T, Td from the temperature T d of the cold-producing medium of compressor 1 ejection.Temperature sensor be provided with can the specific pressure sensor setting implement more at an easy rate.In addition, if pressure sensor is set, then cold-producing medium is revealed from the mounting portion of pressure sensor easily.Therefore, preferred serviceability temperature sensor comes specified pressure PH.

Fig. 2 illustration is used to implement the heat pump that this is calculated.In heat pump 72, between compressor 1 and radiator 2, replaced pressure sensor 21 and disposed the temperature sensor 22 that the temperature T d from the cold-producing medium of compressor 1 ejection is measured.So heat pump also can have the 3rd temperature testing organization of the outer temperature of detection system for specified pressure PH and detect from the 4th temperature testing organization of the temperature of the cold-producing medium of compressor ejection.

Pressure sensor 21 and

temperature sensor

22,23,24,25 all are connected with controller 30, and based on the signal from these sensors, controller 30 is adjusted the aperture of expansion valve 6,7.These sensors are as long as use existing known sensor.Temperature sensor for example can be a thermistor.

Below, the control that utilizes the heat pump 72 (with reference to Fig. 2) that controller 30 carries out is described.At this, illustration with the cycling condition in winter be benchmark determined decompressor 3 driving cylinder volume (correctly saying the ratio of the driving cylinder volume of the relative compressor 1 of driving cylinder volume of decompressor 3) time control.Under this situation, (outside air temperature T) uprises along with the atmosphere temperature outside the system, and it is big that the required value of the discharge capacity of relative expansion machine 3 becomes, if outside air temperature T reaches set point of temperature, then required value surpasses the discharge capacity of decompressor 3.That is, if outside air temperature T reaches more than the setting, then the volume flow of the cold-producing medium in the desire inflow decompressor 3 becomes bigger than driving cylinder volume.

Can't control discretely with the rotating speed of compressor 1 with the rotating speed of the direct decompressor 3 that links of compressor.Therefore,, then need the part of cold-producing medium to be flowed in bypass path, guarantee level and smooth running by open second expansion valve 7 if required value is excessive as mentioned above.But if the part of cold-producing medium flows in bypass path, then the high side pressure PH of freeze cycle reduces, and follows in this, and the degree of superheat SH that flows into the cold-producing medium in the compressor 1 also reduces.If degree of superheat SH diminishes, the cold-producing medium that then produces liquid flows into the trouble in the compressor, thereby can't guarantee the reliability of compressor.In addition, be accompanied by the reduction of high side pressure PH, the efficiency factor of heat pump (COP) also changes.

At reference Fig. 3 and in the control of following explanation, high side pressure is controlled so as to suitable value, also controls refrigerant superheat degree SH.

At first, by import outside air temperature T (step 1 from the signal of temperature sensor 25; S1).Then, contrast outside air temperature T and predefined temperature T a if outside air temperature T more than temperature T a, then transfers to step 3, if outside air temperature T is not enough temperature T a, then turn back to step 1 (step 2; S2).At outside air temperature T is temperature T a when above, and second expansion valve 7 of cutting out is open, the part of cold-producing medium flow in the body 12 that forms bypass path (step 3, S3).

In step S3, can open second expansion valve 7 until predefined regulation aperture, also can open second expansion valve 7 until with the corresponding aperture of temperature difference (T-Ta).Temperature T a for example needs only based on the ratio of the driving cylinder volume of the relative compressor 1 of driving cylinder volume of decompressor 3 and sets.

At this, when outside air temperature T deficiency temperature T a, make second expansion valve, 7 full cut-offs, the whole amount of cold-producing medium flows in the decompressor 3.This control is favourable to the raising of the organic efficiency of the energy that utilizes decompressor 3 and carry out.But, be not limited thereto, also can be before implementation step S3 in advance the part of cold-producing medium be imported bypass path.Under this situation, step S3 is not the control of " second expansion valve that will cut out is open ", but the control of " increasing the aperture of second expansion valve ".

Then, based on signal, calculate the high side pressure PH (step 4 of freeze cycle from

temperature sensor

22,25; S4).Under the situation of the heat pump 71 that possesses pressure sensor 21, as long as intactly use the value of utilizing sensor 21 to try to achieve.Then, reduced pressure PH and predefined goal pressure PH _T, if pressure P H not with goal pressure PH _TUnanimity is then transferred to after the step 6, if consistent, then transfers to (step 5 after the step 9; S5).

High side pressure PH for example calculates based on graph of a relation as shown in Figure 4.Reach from temperature (the ejection refrigerant temperature of the compressor) Td of the cold-producing medium of compressor ejection if determine outside air temperature T, then can obtain from pressure (the ejection refrigerant pressure of the compressor) Pd of the cold-producing medium of compressor ejection.

Goal pressure PH _TBased on the efficiency factor optimization of heat pump and the value that obtains and determining.The value that the efficiency factor of heat pump becomes optimum pressure for example changes corresponding to the heating efficiency (getting 4.5kW, 6.0kW equivalence in hot water supply device) of radiator, outside air temperature (in hot water supply device with go into coolant-temperature gage suitable).The representative factor of efficiency factor being given influence is an outside air temperature.As long as the determination efficiency coefficient becomes optimum value by experiment in advance, and,, determine goal pressure PH as the function of regulation parameter (for example outside air temperature) based on its result _TGet final product.

Goal pressure PH _TPreferably become the optimum consistent value of value (optimal value) with the efficiency factor of heat pump in the operating condition in being applied to heat pump, but do not need strictly consistently, or do not need consistent with it all the time with optimal value.For example, the outside air temperature of scope is set a goal pressure PH in accordance with regulations _TUnder this situation, goal pressure PH _TCorresponding to outside air temperature or entry variation of temperature and change interimly.Predefined like this, be the parameter and the purpose pressure P H of representative with the outside air temperature _TRelation import in advance in the controller 30, determine goal pressure PH based on this parameter definite corresponding to operating condition _T

At pressure P H and goal pressure PH _TWhen unequal, judge that whether pressure P H is than goal pressure PH _T(step 6 greatly; S6).Then, if pressure P H than goal pressure PH _TGreatly, then change the aperture (step 7 of second expansion valve 7 significantly; S7), if pressure P H than goal pressure PH _TLittle, change the aperture (step 8 of second expansion valve 7 then lessly; S8).

If a pressure P H reduces via step 7, if rise via step 8 a pressure P H.Then, turn back to step 4 and calculate pressure P H once more, pressure P H that in step 5, calculates and goal pressure PH _TContrast.So the loop control that repetition is made of step 4～8 is until pressure P H and goal pressure PH _TConsistent.

In this loop control, the degree of the change of step 7 or 8 aperture is preferably very little.This is because if change aperture significantly quickly, then pressure P H becomes and is difficult to converge on goal pressure PH _TNear.

If confirm pressure P H and goal pressure PH in step 5 _TUnanimity, the then control of the high side pressure PH of freeze cycle (first control) finishes for the time being, implements the control (second control) of the degree of superheat SH of cold-producing medium.

In second control, at first, calculate degree of superheat SH (step 9; S9).In heat pump 72,,, calculate degree of superheat SH with reference to the saturated vapor line (particularly) of cold-producing medium with reference to the cold-producing medium evaporating temperature of measuring by temperature sensor 24 based on the temperature of measuring by temperature sensor 23.Then, contrast degree of superheat SH and predetermined target degree of superheat SH _T, if degree of superheat SH not with target degree of superheat SH _TUnanimity is then transferred to after the step 11, if consistent, then turns back to step 4 (step 10; S10).

Setting SH as the target degree of superheat _TAs long as suitably determine, usually, be to be positioned at the value that surpasses this scope below 0 ℃ and 20 ℃ according to the kind of heat pump or cold-producing medium, the service condition of supposition etc.The degree of superheat can utilize temperature difference to represent as mentioned above, but say correctly that the said temperature difference is by the temperature of this cold-producing medium of overheated (superheat) and poor with the represented temperature (boiling point of this pressure) of the intersection point of the saturated vapor line of the pressure of this cold-producing medium.

In order to ensure the reliability of compressor, preferred degree of superheat SH is greater than more than to a certain degree.But if degree of superheat SH is excessive, the power that then needs to drop in the compressor becomes big.If consider this, then setting SH _TPreferably the value more than 5 ℃ is more preferably the value below 10 ℃.If degree of superheat SH is controlled in suitable scope, then can guarantee the reliability of compressor 1, and more than the input of anti-stopping power in compressor 1 become greater than necessity.The suitable control of degree of superheat SH not only helps the raising of the reliability of compressor 1, also helps the further raising of the efficiency factor of heat pump.

At degree of superheat SH and target degree of superheat SH _TWhen unequal, judge that whether degree of superheat SH is greater than target degree of superheat SH _T(step 11; S11).Then, if degree of superheat SH greater than target degree of superheat SH _TThen change the aperture (step 12 of first expansion valve 6 significantly; S12), if degree of superheat SH less than target degree of superheat SH _TChange the aperture (step 13 of first expansion valve 6 then lessly; S13).

If a degree of superheat SH reduces via step 12, if rise via step 13 degree of superheat SH.According to the reason of explanation in step 7,8, the degree of the change of step 12,13 aperture is also preferably very little.This is because by via step 12 or 13, make degree of superheat SH reliably near target degree of superheat SH _T

After having implemented step 12,13, turn back to step 4, implement the control of pressure P H once more.So, in control as shown in Figure 3, after the control (second control) of degree of superheat SH finishes, and then the control of enforcement high side pressure PH (first control).

If only control high side pressure PH, then as TOHKEMY 2003-121018 number open shown in, as long as be implemented in the control that the state of the side's standard-sized sheet that makes expansion valve or full cut-off is adjusted the opposing party's aperture down.With respect to this, in control as shown in Figure 3, after this first control of the aperture of suitably adjusting second expansion valve 7 finishes, under the state (that is, not changing) of the aperture that keeps second expansion valve 7, in second control, adjust the aperture of first expansion valve 6.

Also have, though not expression in Fig. 3, but in heat pump 71,72, also can flow in the little temperature province of the driving cylinder volume of volume flow ratio decompressor 3 of the cold-producing medium in the decompressor 3 in desire, implement to keep making the state of second expansion valve, 7 full cut-offs, and adjust this control of aperture of first expansion valve 6.This control also can implemented between these steps when step 2 turns back to step 1.

In control as shown in Figure 3, confirmed and goal pressure PH at pressure P H _TUnanimity after finish this control, and transfer to the control of degree of superheat SH, but do not confirming and target degree of superheat SH at degree of superheat SH _TThe situation of unanimity under finish this control, and turn back to the control of pressure P H.This is the result of suitable control who has paid attention to the high side pressure PH of freeze cycle more.But, be not limited thereto, also can confirm and target degree of superheat SH at degree of superheat SH _TUnanimity after finish this control.The flow chart that is used to carry out this control as shown in Figure 5.

In example as shown in Figure 5, after step 12 or 13 finishes, turn back to step 9, proceed control.Under this situation, second control also is to repeat until degree of superheat SH and desired value SH _TConsistent loop control.Under the situation that is loop control, sometimes not by whether consistent with desired value, but by degree of superheat SH and desired value SH _TDifference whether at prescribed limit SH _DRIn, the judgement that comes implementation step 10 is suitable.Other steps of control as shown in Figure 5 and the control example of Fig. 3 are similarly implemented.

Except change as shown in Figure 5, also can apply all changes to the control of pressure P H and degree of superheat SH.Control of the present invention is not limited to the control example shown in Fig. 3,5.

For example, in the above description, with pressure P H and goal pressure PH _TWhether consistent, in other words, with pressure P H and goal pressure PH _TDifference whether be 0 for judging object, but also can replace, with pressure P H and goal pressure PH _TDifference whether at prescribed limit PH _DRInterior for judging object.Under this situation, as long as step of replacing 5 is judged pressure P H and goal pressure PH _TDifference whether at prescribed limit PH _DRInterior getting final product.Whether difference is at prescribed limit PH _DRIn judgement also can be undertaken by directly calculating difference, for example also can be by calculating ratio, and judge this than whether be converted into this than prescribed limit PH _DRIn carry out.With regard to the control of degree of superheat SH, too.

Prescribed limit PH _DR, SH _DRSize if the purposes by heat pump etc. suitably set, but preferably by suitable restricted portion.If enumerate an example, then prescribed limit PH _DRBy deducting goal pressure PH from pressure P H (MPa) _T(MPa) value that obtains is represented, preferably-and more than the 1.2MPa and below the 1.2MPa, and then-more than the 0.8MPa and below the 0.8MPa.Prescribed limit SH _DRBy from degree of superheat SH (℃) deduct target degree of superheat SH _T(℃) and the value that obtains is represented, is preferably set to surpass-(SH _T) ℃ and below 20 ℃ and then surpass-(SH _T) ℃ and the scope below 10 ℃, for above-mentioned value for negative, for example also can be with prescribed limit SH _DRBe set at and surpass 0 ℃ value.So-called " surpassing-(SH _T) ℃ and below 20 ℃ " at target degree of superheat SH _TBe under 10 ℃ the situation, to be the scope of " surpassing below-10 ℃ and 20 ℃ ".

In addition, for example, also can be after step 8, append and judge the whether step of full cut-off of second expansion valve 7, in the step that this appends,, then turn back to step 1 if be judged as second expansion valve, 7 full cut-offs.In the step of appending,, then turn back to step 4 and repeat control if be judged as not full cut-off of second expansion valve 7.

In addition, for example, also can before the control of pressure P H, carry out the control of degree of superheat SH, implementation step 9 after step 3.Under this situation, control degree of superheat SH, then controlled pressure PH, and then control degree of superheat SH.Also can be according to the purposes or the design content of heat pump, implementation step 1～3, begins control from step 4 or 9.

As described above described, controller (control device) 30 is at the high side pressure PH of cold-producing medium with as the setting PH of target _TDifference not at prescribed limit PH _DRWhen interior, implement the pressure control (first control) of the aperture of change second expansion valve (second throttling arrangement) 7, make pressure P H and setting PH _TThe absolute value of difference diminish that (pressure P H approaches setting PH _TPoor) (S4～S8).

Then, after first control finishes, the setting SH of the degree of superheat SH of the cold-producing medium in flowing into compressor and predetermined positive value _TDifference not at prescribed limit SH _DRWhen interior, implement the degree of superheat control (second control) of the aperture of change year first expansion valve (first throttle device) 6, make degree of superheat SH and setting SH _TThe absolute value of difference diminish that (degree of superheat SH approaches setting SH _T) (S9～S13).

In first control, control device preferably changes second throttling arrangement, makes pressure P H and setting PH _TDifference reach prescribed limit PH _DRIn.In addition, in second control, control device can change the first throttle device, makes degree of superheat SH and setting SH _TDifference reach prescribed limit SH _DEIn.

As described in above-mentioned control row, control device also can be after second control finishes, at pressure P H and setting PH _TDifference not at prescribed limit PH _DRWhen interior, further implement first control.This is that H controls again to pressure P for the variation of the pressure P H that considers the second control generation.

As illustrated in above-mentioned, as concrete control, first control in, when pressure P H than setting PH _THeight, and pressure P H and setting PH _TDifference not at prescribed limit PH _DRThe time, increase the aperture of second throttling arrangement, when pressure P H than setting PH _TLow, and pressure P H and setting PH _TDifference not at prescribed limit PH _DRThe time, reduce the aperture of second throttling arrangement.

In addition, second control in, when degree of superheat SH than setting SH _THeight, and degree of superheat SH and setting SH _TDifference not at prescribed limit SH _DRThe time, increase the aperture of first throttle device, when degree of superheat SH than setting SH _TLow, and degree of superheat SH and setting SH _TDifference not at prescribed limit SH _DRThe time, reduce the aperture of first throttle device.

In as Fig. 3,5 illustrative controls, respectively the value of specified pressure PH and degree of superheat SH is particularly adjusted expansion valve, controlled pressure PH and degree of superheat SH thus based on this value.But the control of pressure P H and degree of superheat SH can be used the replacement parameter related with pressure P H or degree of superheat SH and carry out indirectly.

For example, also can measure the ratio RV that the volume flow that flows into the cold-producing medium in the compressor 1 flows into the volume flow of the cold-producing medium in the decompressor 3 relatively at the control of the high side pressure PH of freeze cycle, measure based on the ratio RC of the volume of the volume relative expansion machine 3 of this RV and compressor 1.Magnitude relationship than RV and RC is the replacement parameters R P related with high side pressure PH, also can set and goal pressure PH at this parameter _TRelated control target RP _T

So in above-mentioned control, control device also can not direct reduced pressure PH and setting PH _T, but the characteristic RP of the contrast regulation related with pressure P H and with setting PH _TRelated setting RP at this characteristic RP _T, judge pressure P H and setting PH thus _TDifference whether at prescribed limit PH _DRIn.

Fig. 6 represents to utilize the variation of the freeze cycle that above-mentioned control carries out.Initial freeze cycle (a ₁～f ₁) if change significantly need make than goal pressure PH in first control _TThe aperture of second expansion valve 7 that high high side pressure reduces is then to freeze cycle (a ₂～f ₂) shift.This freeze cycle is if change the aperture of first expansion valve 6 that need guarantee the big relatively degree of superheat lessly, then to freeze cycle (a in second control ₃～f ₃) shift.This freeze cycle is if change the aperture of second expansion valve 7 that need make the high side pressure reduction significantly, then to freeze cycle (a in first control of implementing once more ₄～f ₄) shift.

Also have, as shown in Figure 6, if make the high side pressure of freeze cycle become supercriticality, then the height pressure reduction in freeze cycle becomes big, and it is big that the contribution of the energy recovery function of decompressor 3 becomes.In order to realize this situation, so long as the heat pump of compressor compresses cold-producing medium gets final product.

The structure that can use heat pump of the present invention is not limited to Fig. 1,2 example.For example, in Fig. 1,2, body 12 has formed the bypass path of the bypass decompressor 3 and first expansion valve 6, but also can be to be connected the feasible heat pump 73 (with reference to Fig. 7) that forms the bypass path of a bypass decompressor 3 with body 11.In addition, also can be the bypass path that body 12 forms a bypass decompressor 3, and first expansion valve 6 be disposed at the heat pump 75 (with reference to Fig. 9) in the downstream of decompressor 3.In these structures,, can suitably control high side pressure PH and degree of superheat SH by using and above-mentioned same control.

In addition, also can a plurality of controllers share and undertake the function of controller 30.In heat pump 76 as illustrated in Figure 10, first controller 31 is undertaken function (S4～S8, the S10～S13) of the aperture of adjusting first expansion valve 6 and second expansion valve 7 for controlled pressure PH and degree of superheat SH, second expansion valve 32 is undertaken acceptance from the signal of

temperature sensor

23,24 and calculate the function (S9) of degree of superheat SH, the 3rd expansion valve 33 is undertaken and is measured outside air temperature T, and opens the control (S1～S3) of second expansion valve 7 according to its result.

In addition, also can be the heat pump that has disposed cross valve 51,53.Can be used as air conditioner as the illustrative heat pump 77 of Figure 11 and use, described air conditioner can utilize the switching of

cross valve

51,53 to select warm running of system and cooling operation.When the warm running of system, the path that selection is represented by solid line in

cross valve

51,53, outdoor heat converter 54 is brought into play function as radiator, and indoor heat converter 52 is brought into play function as evaporimeter.In this heat pump 77,, then can suitably control high side pressure PH and degree of superheat SH if use above-mentioned illustrated control.

In above-mentioned illustrative control, measure from the pressure P d (PH) of the cold-producing medium of compressor ejection, or measure from the temperature of the cold-producing medium of compressor ejection in order to calculate this pressure P H.Also can utilize this to operate countermeasure when carrying out heat pump unusual.Specifically, in having the heat pump of above-mentioned illustrative structure, when pressure P H surpasses the critical pressure of regulation and/or when the temperature of the cold-producing medium that sprays from compressor 1 surpasses the critical-temperature of regulation, controller 30 can be implemented countermeasure when unusual by taking following countermeasure, be that controller 30 identification is unusual, the aperture of first thermal expansion valve 6 and/or second thermal expansion valve 7 is adjusted into more than the aperture of regulation significantly.At this, the aperture that the aperture of regulation is set at the size that surpasses the control range of being determined by first control and second control is for well.By this countermeasure, the pressure of cold-producing medium and temperature are reduced apace.

If like this control,, also can eliminate this exceptional value at short notice even then want because of the rapid variation of operating condition or certain thereby reach under the situation of exceptional value in the high side pressure PH of cold-producing medium or temperature.Also have, critical pressure and critical-temperature are different because of the structure of cold-producing medium or heat pump etc., but if narration has been used the situation of carbon dioxide as cold-producing medium, but then as critical pressure illustration 12MPa, but as 115 ℃ of critical-temperature illustrations.

In order to carry out above-mentioned countermeasure when unusual, when heat pump of the present invention surpasses the critical pressure of regulation at pressure P H, or when the temperature of the cold-producing medium of compressor ejection surpasses the critical-temperature of regulation, control device preferably surpass first control and second control aperture the change scope and change at least one side's who selects from first throttle device and second throttling arrangement aperture significantly.

Figure 12 and Figure 13 represent to be set at as cold-producing medium used carbon dioxide and make the on high-tension side pressure of freeze cycle surpass carbon dioxide critical pressure situation (Figure 12) and used cold-producing medium in the evaporimeter of situation (Figure 13) in fluorine Lyons as cold-producing medium and the variations in temperature of air (being heated gas).In either case, cold-producing medium is all in temperature T ₀The time inflow radiator in, add hot-air by heat exchange with air.The temperature difference Δ T that temperature difference Δ T when being cold-producing medium with the carbon dioxide becomes when being cold-producing medium with fluorine Lyons is big.This is because different with fluorine Lyons, carbon dioxide does not carry out phase change in radiator.Carbon dioxide is suitable as the cold-producing medium that is used for heated medium is heated to be high temperature.

(industrial utilizability)

The present invention locates as air conditioner, hot-warer supplying machine, tableware drier, house refuse drying in improvement Reason machine etc. and have high value on the useful heat pump.

Claims

1. heat pump has:

Compressor; Radiator; Decompressor; Evaporimeter;

Body, it forms cold-producing medium in order via described compressor, described radiator, described decompressor, and described evaporimeter and the circulating path that circulates, and the bypass path that do not flow to described evaporimeter from described radiator via described decompressor of cold-producing medium;

The first throttle device, it is disposed between described radiator and the described decompressor or on the described circulating path between described decompressor and the described evaporimeter, and aperture is variable;

Second throttling arrangement, it is disposed on the described bypass path, and aperture is variable;

Control device, it adjusts the aperture of described first throttle device and the aperture of described second throttling arrangement,

Described compressor and described decompressor are connected with identical rotating shaft,

Described control device,

Implement first control, described first control is, reaches optimum value and definite setting PH as the high side pressure PH of the cold-producing medium that circulates in described circulating path with based on the efficiency factor of heat pump _TDifference not at prescribed limit PH _DRWhen interior, the aperture that changes described second throttling arrangement makes described pressure P H and described setting PH _TThe absolute value of difference diminish,

After described first control finishes, implement second control, described second implements control is, as the degree of superheat SH of the cold-producing medium that flows into described compressor with as the setting SH of predetermined positive value _TDifference not at prescribed limit SH _DRWhen interior, the aperture that changes described first throttle device makes the described degree of superheat and described setting SH _TThe absolute value of difference diminish.

2. heat pump as claimed in claim 1, the aperture of described control device described second throttling arrangement of change in described first control makes described pressure P H and described setting PH _TDifference reach described prescribed limit PH _DRIn.

3. heat pump as claimed in claim 1, the aperture of described control device described first throttle device of change in described second control makes described degree of superheat SH and described setting SH _TDifference reach described prescribed limit SH _DRIn.

4. heat pump as claimed in claim 1, described control device is after described second control finishes, at described pressure P H and described setting PH _TDifference not at prescribed limit PH _DRWhen interior, further implement described first control.

5. heat pump as claimed in claim 1, wherein, in described first control,

At described pressure P H than described setting PH _THeight and described pressure P H and described setting PH _TDifference not at described prescribed limit PH _DRWhen interior, increase the aperture of described second throttling arrangement,

At described pressure P H than described setting PH _TLow and described pressure P H and described setting PH _TDifference not at described prescribed limit PH _DRWhen interior, reduce the aperture of described second throttling arrangement.

6. heat pump as claimed in claim 1, wherein, in described second control,

At described degree of superheat SH than described setting SH _THeight and described degree of superheat SH and described setting SH _TDifference not at described prescribed limit SH _DRWhen interior, increase the aperture of described first throttle device,

At described degree of superheat SH than described setting SH _TLow and described degree of superheat SH and described setting SH _TDifference not at described prescribed limit SH _DRWhen interior, reduce the aperture of described first throttle device.

7. heat pump as claimed in claim 1, wherein, described setting SH _TBe to be in the numerical value that surpasses this scope below 0 ℃ and 20 ℃.

8. heat pump as claimed in claim 1 wherein, also has first temperature testing organization that detects the temperature that flows into the cold-producing medium in the described compressor and second temperature testing organization that detects the temperature of the cold-producing medium in the described evaporimeter.

9. heat pump as claimed in claim 1 wherein, also has the pressure detecting mechanism of detection from the pressure of the cold-producing medium of described compressor ejection.

10. heat pump as claimed in claim 1 wherein, also has the 3rd temperature testing organization of the outer temperature of detection system and detects from the 4th temperature testing organization of the temperature of the cold-producing medium of described compressor ejection.

11. heat pump as claimed in claim 1, wherein, described control device does not directly contrast described pressure P H and described setting PH _T, but the characteristic RP by the contrast regulation related with described pressure P H and with described setting PH _TRelated, at the setting RP of this characteristic RP _TJudge described pressure P H and described setting PH _TDifference whether at described prescribed limit PH _DRIn.

12. heat pump as claimed in claim 1, wherein, when described pressure P H surpasses the critical pressure of regulation or when the temperature of the cold-producing medium of described compressor ejection surpasses the critical-temperature of regulation, described control device is adjusted into the aperture of at least one side in described first throttle device and described second throttling arrangement more than the aperture of regulation significantly, wherein, the aperture of regulation is set at the aperture of the size that surpasses the control range of being determined by described first control and described second control.

13. heat pump as claimed in claim 1, wherein, described compressor reaches the mode compressed refrigerant of supercriticality according to the cold-producing medium from described compressor ejection.