The present invention relates to a conditioning system of the free cooling type for environments and particularly for computing centers, to a method of operation of such system, and to an apparatus for carrying out such method.
Conditioning systems of the free cooling type are known today and are widespread, for environments and particularly for computing centers, of the type comprising:
Usually an evaporative conditioning unit, i.e. with cooling means using water, is set up to optimize the overall cost of electricity and water.
On the market, however, such conditioning units are usually set at the factory to start by default with operation using water once the air has reached a certain dry-bulb temperature, therefore irrespective of the outside humidity.
Such setting is performed on the basis of a specific demand for cooling, without taking account of any variations of that demand.
Furthermore, since such default operation setting does not take account of the actual efficacy of the evaporative system at different relative humidity levels for the same outside temperature, this means that before actuating the external fans at maximum speed in dry mode, i.e. without engaging the evaporative means, in order to provide the cooling power required, the unit starts using water anyway in order to obtain an evaporative cooling effect.
The aim of the present invention is to provide a conditioning system of the free cooling type for environments and particularly for computing centers, which is capable of also optimizing consumption based on any variations of the demand for cooling.
In particular, an object of the invention is to provide a conditioning system that is capable of evaluating the actual efficacy of the evaporative system at different relative humidity levels for the same outside temperature.
Within the above aim, an object of the invention is to provide a method of operation of such system.
Another object of the invention is to provide an apparatus for carrying out such method.
This aim and these and other objects which will become better apparent hereinafter are achieved by a conditioning system of the free cooling type for environments and particularly for computing centers, of the type comprising:
said conditioning system being characterized in that it comprises:
Further characteristics and advantages of the invention will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the conditioning system according to the invention, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:
With reference to the figures, a conditioning system of the free cooling type for environments and particularly for computing centers is generally designated with the reference numeral 10.
Such conditioning system 10 comprises:
The peculiarity of the conditioning system 10 according to the invention consists in that it comprises:
The conditioning unit 11 is, for example, of the indirect free cooling type, with an air/air exchanger 12.
In a variation of embodiment, the conditioning unit 11 also comprises an auxiliary cooling device 26, which is constituted example by a direct-expansion cooling circuit or constituted by a cooled-water system; it is installed within the conditioning unit 11 in order to provide standby auxiliary cooling power or to supplement the cooling power supplied by the evaporative cooling means using water 16.
The evaporative cooling means 16 comprise, in the present embodiment:
In a different embodiment, not shown for the sake of simplicity, the air conditioning unit 11 is of the direct free cooling type; in such case the first fans are arranged in output from an environment to be air-conditioned, and the warm air exits to the outside directly from the environment to be air-conditioned.
The conditioning unit 11, in the embodiment described herein, comprises cooling means using water 31 for the secondary air flow 14 at the inlet of the conditioning unit 11; such cooling means using water 31 may also be absent.
The cooling means using water 31 take the form for example of a series of atomization nozzles 32 which are adapted to atomize water in the primary air flow 13 in the corresponding inlet region 33 of the primary air flow in the conditioning unit 11.
The atomization nozzles 32 are optionally served by a pressurization pump 34 which in turn is preceded by a water filter 35.
The atomization nozzles 32 can be substituted by an adiabatic mat, of conventional type, which performs the same function.
The figures show for the purposes of example a water line 36 for feeding the conditioning unit 11, which can take the form of a pipe of a water mains or a pipe from another water source.
The temperature and humidity detection means for the primary air flow 13 at the inlet of the conditioning unit 11 are constituted by a first probe 19, which is arranged so as to intercept the primary air flow 13, which arrives from the environment to be air-conditioned 15, at an inlet region 37 of the conditioning unit 11.
The temperature and humidity detection means for the primary air flow 13 at the outlet of the conditioning unit 11, i.e. at an outlet region 38 from the unit 11 and at the inlet of the environment to be air-conditioned 15, have a second probe 20.
The means for detecting the temperature and humidity for the secondary air flow 14 at the inlet of the conditioning unit 11 are constituted by a third probe 21, which is arranged so as to intercept the secondary air flow 14, which arrives from the outside environment, in the corresponding inlet region 33 of the conditioning unit 11.
The means for detecting the temperature and humidity for the secondary air flow 14 at the outlet of the conditioning unit 11, i.e. at an outlet region 39 from the unit 11 toward the outside, have a fourth probe 22.
The means for detecting the flow-rate of the primary air flow 13 are constituted by a fifth probe 23, which is arranged in the outlet region 38 from the conditioning unit 11 toward the environment to be air-conditioned 15.
The fifth probe 23 is constituted, for example, by a hot-wire anemometer, or by a differential pressure probe, or by another type of commercially-available anemometer adapted to the range of flow-rate and air considered.
The means for detecting the flow-rate of the secondary air flow 14 are constituted by a sixth probe 24, which is arranged at the outlet region 39 of the secondary air flow 14 from the conditioning unit 11 toward the outside.
Such sixth probe 24 is constituted, for example, by a hot-wire anemometer, or by a differential pressure probe, or by another type of commercially-available anemometer adapted to the range of flow-rate and air considered.
The conditioning system 10 according to the invention, once activated, is capable, by way of the electronic control unit 25 and of the detection means connected thereto, of predictively recalculating what the operating cost will be without the use of water or with a variable use of water; selection of one or the other operating mode is made on the basis of an instant optimization of the costs.
With the variation of the outside humidity and temperature and of the demand for cooling, the electronic unit 25 is capable of re-designating what is the most economic operating mode.
This is as applicable to a system according to the invention of the direct free cooling type as it is to a system according to the invention of the indirect free cooling type.
The invention also relates to a method of operation for a conditioning system 10 according to the invention as described above; the following symbols are used hereinbelow:
Tamb=temperature of the outside air used for the free cooling, measured by the third probe 21;
Hamb=humidity of the outside air used for the free cooling, measured by the third probe 21;
Tsupply=temperature of the primary air flow 13 at the outlet from the conditioning unit 11 and at the inlet to the environment to be air-conditioned 15, measured by the second probe 20;
Hsupply=humidity of the primary air flow 13 at the outlet from the conditioning unit 11 and at the inlet to the environment to be air-conditioned 15, measured by the second probe 20;
Tret=temperature of the primary air flow 13 at the inlet to the conditioning unit 11, i.e. returning from the environment to be air-conditioned 15, measured by the first probe 19;
Hret=humidity of the primary air flow 13 at the inlet to the conditioning unit 11, i.e. returning from the environment to be air-conditioned 15, measured by the first probe 19;
Tex=temperature of the secondary air flow 14 at the outlet from the conditioning unit 11 toward the outside, measured by the fourth probe 22;
Hex=humidity of the secondary air flow 14 at the outlet from the conditioning unit 11 toward the outside, measured by the fourth probe 22;
Q1=flow-rate of the primary air flow 13, measured by the fifth probe 23;
Q2=flow-rate of the secondary air flow 14, measured by the sixth probe 24.
Such method of operation according to the invention is characterized in that it comprises the following operations, represented by the block diagram in
Such cycle of operations is repeated iteratively.
The cost of dry operation of the system (Cdry) is a function of the estimated, or calculated, power (Pdry) absorbed by the fans 17 and 18 during the operation of the conditioning unit 11 without using water, i.e. with the evaporative means 16 and the cooling means 31 inactive.
The cost of wet operation of the system (Cwet) is a function of the estimated, or calculated, power (Pwet) absorbed by the fans 17 and 18 with the conditioning unit 11 operating using water, and of the consumption of water W.
In order to determine Pdry, we proceed with the following operations:
Rdry=f(Tamb,Tret,Ts-p)
Q2dry=Rdry*Q1
S2dry=Cspeed1*Q2dry+Cspeed2
such value shown schematically by block 56, with Cspeed1 and Cspeed2 which are coefficients obtained from the characteristics of the fans,
Pdry=Cpower1*(S2dry)̂Cpower2
such value shown schematically by block 58, with Cpower1 and Cpower2 which are also coefficients obtained from the characteristics of the fans.
In order to determine Pwet, we proceed with the following operations, which are shown schematically in
Tadiab=CTA1+CTA2*Tamb+CTA3*(Tamb)̂2+CTA4*(Tamb)̂3
such value shown schematically by block 64, with CTA1, CTA2, CTA3 and CTA4 which are function coefficients of Hamb, obtained from the psychometric or Carrier chart.
Rwet=f(Tadiab,Tret,Ts-p)
Q2wet=Rwet*Q1
S2wet=Cspeed1*Q2wet+Cspeed2
Pwet=Cpower1*(S2wet)̂Cpower2
W=(CW1+CW2*Hamb+CW3*(Hamb̂2)+CW4*(Hamb̂3))*Q2wet+CW5
such value shown schematically with block 72, with the coefficients CW1, CW2, CW3, CW4, CW5 which are obtained from the consumption of water of the evaporative cooling means using water 16.
In order to determine Cdry and Cwet, we proceed with the following operations, which are shown schematically in
Cdry=Kp*Pdry
with the operation shown schematically by block 75 and the resulting value of Pdry shown schematically by block 76;
Cwet=G*Kw*W+Kp*Pwet
such value shown schematically with block 82, with G which is a factor that depends on the outside humidity, the value of which is:
G=0.5 for Hamb>45%, high outside humidity and a single pump 29 of the evaporative cooling means using water 16 is in use;
G=0.7 for 30%<Hamb≦45%, average outside humidity and two pumps 29 and 30 of the evaporative cooling means using water 16 are in use;
G=1.05 for Hamb≦30%, low outside humidity, two pumps 29 and 30 of the evaporative cooling means using water 16 are in use and, if present, cooling means using water 31 for the secondary air flow 14 at the inlet are active.
If Cdry is greater than Cwet, then switch on the evaporative cooling means 16 and/or the cooling means using water 31, as in block 45.
If Cdry is not higher than Cwet, but the temperature of the outside environment (Tamb) is higher than the return temperature Tret of the primary air flow 13 at the inlet to the conditioning unit 11, switch on the evaporative cooling means 16 and/or the cooling means using water 31 for the secondary air flow 14 at the inlet.
If Hamb<90% or Tamb>18° C., the electronic control unit 25 is set to force the operation of the conditioning unit 11 in dry mode.
When the wet operating mode is selected, if Hamb>45% only one pump 29 of the evaporative cooling means 16 is actuated; if Hamb≦45% two pumps 29 and 30 of the evaporative cooling means 16 are actuated; if Hamb≦30% two pumps 29 and 30 of the evaporative cooling means 16 are actuated and the cooling means using water 31 for the secondary air flow 14 at the inlet, if present, are active.
The invention also relates to an apparatus for carrying out a method of operation of the conditioning system described above.
Such apparatus is characterized in that it comprises:
In practice it has been found that the invention fully achieves the intended aim and objects.
Such method of operation of the conditioning system according to the invention, once operational, on the basis of the readings of the detection means, is capable of predictively determining what the operating cost will be without the use of water and what the operating cost will be with variable use of water.
Selection of one or the other operating mode is made automatically by the electronic control unit 25 on the basis of an instant optimization of the costs Cdry and Cwet.
With the variation of the outside humidity and temperature and of the demand for cooling, the method of operation determines which is the most economic operating mode.
Such method of operation is as valid for systems with direct free cooling as for systems with indirect free cooling, like the one described above.
With the invention a conditioning system and a method for its operation are therefore provided which make possible a continuous optimization of the operating costs on the basis of the operating conditions.
In particular, with the invention a conditioning system and a method for its operation are provided which make it possible to vary the parameters constituted by the local costs of electricity and water if these should change, and to obtain a new optimized solution.
Moreover, with the invention a conditioning system and a method for its operation are provided which make it possible to set the automatic selection of the operating mode on the basis of two different costs of electricity, a nighttime rate and a daytime rate, so that the electronic control unit can re-parametrize the optimization on the basis of the time of day.
Furthermore, with the invention a conditioning system and a method for its operation are provided which make it possible to include in the cost not only the power absorbed by the fans and water, but also other, optional backup systems such as a cooling circuit or a refrigerated water system, and optimize the cost of the whole.
The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.
In practice the components and the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. PD2014A000352 (102014902318551) from which this application claims priority are incorporated herein by reference.
Number | Date | Country | Kind |
---|---|---|---|
PD2014A000352 | Dec 2014 | IT | national |