Title of Invention

METHOD FOR REGULATION OF DISPLACEMENT CONDITIONERS, AND SYSTEM

Abstract Corrbined regulation of the power supplied by the conditioner and of the air flow rate of the conditimer is carried out so as to maintain the the temperature gradient between air entering and air leaving the same conditioner high, in order to allow perfect functioning of d1spacenent system (without mixing )in any conditin of service.
Full Text METHOD FOR REGULATION OF DISPLACEMENT CONDITIONERS, AND SYSTEM
DESCRIPTION
The present invention relates to the field of cooling of objects by means of displacement ventilation.
According to the so-called technique of "displacement", in itself laiown, in a room a flow of cold air is supplicd at low speed at floor level.
The conditioner or re&igerator which supplies this flow can be outside or inside the room. The culd air, denser, is spread over tlic entire floor. Wlien the cold air comes into contact with the heat sources in the room, for example equipment to be cooled, it heats and an ascending movement is generated by convection. The heated air near the ceiling of the room is aspirated by the conditioner, cooled and returned mto circulation. The features which distinguish displacement ventilation are the low speed of the air, for which some books define the upper limit of 0.5 m/s, and the fact that the cooling ah, that is to say the ah emitted by the conditioner, which air passes along the heat sources to be cooled and returns to the conditioner, is not mixed with the ambient air, or only mixes with it minimally.
Cooling of the displacement air can be carried out both with air diffusers placed mside the room to be cooled; cormected to air conditioners placed externally via a networlc of ducts, or directly with air conditioners placed inside the room.
The movement of coohng air in a displacement system is caused by the thermal gradient between the cold cooling air at floor level and the heated coohng air at ceiling level It is therefore decisive to maintain this thermal gradient close to the design value or above a preset limit for proper working of the system.
An object of the invention is to maintain the gradient always above a certain hmit value.
The thermal gradient is linlced to the air flow rate and to the heal load of the room. At the same air flow rate, the gradient is greater if the! heat load is greater. At the same heat load, the gradient is greater if the air flow rate is lower.

The heat load of a room depends on the endogenous heat emitted by the equipment located in the room, on the endogenous heat emitted by the persons, In the mom, and on the heat exchanged via the structures (walls, floor, ceiling) between the room and the outside.
The heat load varies in time substantially because both the endogenous heat emitted by the equipment and by the persons and the heat exchanged, wliich depends on the conditions inside and outside the room, vary.
According t» the state of art prior to this invention, in systems with displacement cooling regulation takes place by controlling the power supplied by the conditioner. The traditional system however does not succeed in preventing variations in the temperature gradient completely and, when the temperature gradient decre^es excessively, this prevents proper fimctioning of the displacement system.
To avoid the problems mentioned, provision is made for the regulation method according to the invention, as claimed in claim 1 and the system as claimed in claim 7. "Further new and useful features are claimed in the dependent claims. The method of regulation, ui other words, provides for joint and sequential regulation of the power suppHed by the conditioner and of the air flow rate of the conditioner. The regulation can be of the modulating type both for the air flow rate and for the power. Or modulating regulation of the power and regulation by discrete steps for the air flow rate can be provided. Or regulation by discrete" steps of the air flow rate and of the power can be provided. Or finally modulating regulation of the air flow rate and discrete step regulation of the power can be provided.
The new regulation method achieves the objects stated above and remedies the disadvantages described above relating to the state of the art. In particular it maintains the temperature gradient always equal or very close to the design value. Moreover there is an advantage as regai-ds the electricity consumption of the fans, in that the power that they must supply decreases strongly as the ambient temperature decreases.
Noii"liiniling examples of cmbodinicnls of the invention are lo be described herein below with reference to the accompanying drawings, in"which:

Fig, I is a graph which iUuslratcs the meUiod of regulation of the invention in the case of
modulating regulation of both the air flow rate and power supplied by the conditioner
(both plotted on the Y axis), as a function of llie power required by the system (or system
load, plotted on the X axis); the air flow rate is indicated by an unbroken line, and the
power supplied by the conditioner is indicated by a dotted Une;
Fig. 2 is a graph for the case of Fig. 1, wherein the modulation of the air flow rate and the
power of tire conditioner are plotted as a function of the temperature ineasured (X axis);
the graphic signs for the air flow rate and for the power supplied by the conditioner,
plotted on the Y axis, arc the same as in Fig. 1;
Fig. 3 is a graph which illustrates an advantage of the invention, in the case of regulation
as in Fig- I; in particular the fact that the temperature gradient (on the Y axis), is
maintained constant while the air temperature varies (on the X axis), the unbroken line
indicates the trend of the tem])eratuvc gradient willi triiditiona! regulation, the dotted line
illustrates the trend of the temperature gradient with regulation according to the
invention; the thicker, horizontal, dashed line indicate.^ the design gradient for proper
displaccrneiil functioning;
Fig. 4 is a graph which illustrates another advantage of the invention, i.e. reduction of the
fan consumption; the fan consumption rates ai"e indicated on the Y axis as a function of
the air temperature, plotted on the X axis: the unbroken line indicates the consumption
for tra^litional regulation, the dotted line indicates the consumption for regulation
according to the invention, in the case of a direct current fan; the chequered line indicates
the consumption for regulation according to the invention, in the case of an alternating
current fan;
Fig. 5 is a gi"aph wliich illustrates the regulation method in the embodiment with stepped
regniation of the air flow rate (on the Y axis as an unbroken hne) and modulating
regulation of the power (on the Y axis as a dotted Une) as a function of the power
required by the system (on the X axis);
Fig. 6 illustrates the embodiment of the invention as for Figure 5, but the air flow rate
and the power supplied by the conditioner, indicated by the same graphic form as for Fig.
5. are plotted as a function of the air temperature;
Fig. 7 illustrates the trend of the temperature gradient (on the Y axis) as a function of the
air temperature (on the X axis), for traditional regulation (unbroken line) and for
regulation as in Fig. 6 (dotted hne), and the design gradient (thick, horizontal, dashed
line);
Fig. S illustrates the consumption of the fan (on the Y axis) as a function of the ah
temperature (on the X axis) for traditional regulation (unbroken hne) and for regulation

as ill Fig. 6, in the case of a fan with direct cim-ent supply (dotted line) and in the case of
a fan with alternating current supply (chequered line);
Fig. 9 illustrates in a first graph (a) stepped regulation of the air flow rale (unbroken line)
with constant power supplied by the conditioner (dotted line), and in a second graph (b)
stepped regulation both of the air flow rale (unbroken line) and of the power supplied by
the conditioner (dotted iiue), in both cases as a function of the power required by the
system;
Fig. 10 illustrates in a graph, as a function of the air temperature, stepped regulation of
the air flow rate (unbroken line) and of the power supplied by the conditioner (dotted
line);
Fig. 11 illustrates in a graph as a function of the air temperature, the temperature gradient
obtained for traditional regulation (unbroken line) and for regulation according to Figures
9 and 10 (dotted line); the design gradient is shown by the thick, horizontal, dashed line;
Fig. 12 illustrates in a graph the advantages for the consumption of the fan as a function
of the air temperature; the consumption of the fan is plotted on the Y axis as an unbroken
hne for traditional regulation, as a dotted line for regulation according to Figures 9 and
10 and for a direct current fan, as a chequered line for an alternating current fan and
regulation as in Figures 9 and 10;
Figs. 13 and 14 refer to an embodiment with modulating regulation of the ah flow rate (unbroken line) and stepped regulation of the power supplied by the conditioner (dotted line); on the X axis in Fig. 13 the power required by the system is plotted and m Fig. 14 the air temperature.
The object of this patent application is a method of regulation of conditioners for a room, functioning according to the displacement principle or the like, and hence a regulation method which allows constant maintaining, in the room to be conditioned, of a design temperature gradient or higher than the design gradient, irrespective of the power required by the same room, According to the new method combined regulation is carried out of the power suppUed by the conditioner and of the air flow rate of the conditioner. The air flow rate can be varied by varying the number of re-\"s of the fan or by using air locks, or in another manner.
According to the new method, more paiticularly, a variation in the air temperature is measured, indicating the variation in the load required (ol" the powci- rcqnired) by tiic system, by means of sensors placed inside or outside the conditioner. Tiie temperature measured can be that of the delivery air, or of the return air, or both. As a function of the

Ihis/these tempcraLurc/s measured the air flow rate and power are regulated, so as to maintain the gradient substantially at the preset value.
The combined regiikiiitii) ofthe iiir Mow ra(c and of tlic powci" can he carried oiii in various ways.
Figures 1-4 refer to a first embodiment of the invention, whereby "modulating" regulation is carried out both of the air ilow rate and of the power. In tliis text the term "modulating" refers to a variation of the parameter controlled (power and/or flow rate) with continuous functioning, without any discontinuity. In the first embodiment, al 100% of the power required by the system, both the power supplied by the conditioner and the air flow rate are 100% (design data). As the load or power required by the system decreases, both arc reduced, according to any trend. Figures 1 and 2 illustrate a linear variation. Provision is made for the air flow rate not to drop below a minimum value so as to improve the sensitivity of the temperature sensors and/or for rnoving in any case the air in the room. In practice regulation of the air flow rate and of the power is carried out as a consequence of the air temperatures measured, as shown in Fig. 2, rather than as a consequence of the measurement of the load required, the temperatures being indicative of this load. The regulation of both parameters (power of the conditioner and air flow rate) takes place within a certain regulation range, defined by vertical dashed lines in Fig. 2. The widtli of the regulation range is iiTelevant and only depends on the control precision to be obtained. Widiin this range the regulation method described above is apphed.
With the regulation method described above, the temperature gradient is maintained constant and equal to 100% (design value), while widi die traditional regulation method, based on regulation of the power of the conditioner alone, the gradient decreased even as far as values such as to prevent proper functioning of the system according to the displacement principle. Moreover a significant advantage is obtained as regards electricity consumption of the fans, as shown in Fig. 4, in the case of variation of the flow rate taking place by modifying the revs of the fan itself That is to say, whereas with the traditional regulation method the consumption of the fans was always equal to 100%, according to the variation in tiic ambicnl lempcraliire, with tlic melhoci of regulalioii shown in Figs. 1 and 2 there is a considerable reduction in the coiLsumption of the fan/s, to a different extent for alternating current fans and for direct cun"ent fans.

A second embodiment of the invention is illustrated with reference to Figures 5-8. M 100% of the power required by the syslcm both the power supplied by the conditioner and tiie air flow rate arc equal to 100% (design data). The regulation is carried out by varying, by discrete steps (any number of steps) the air flow rate, and contiotiously, with any trend (modulating variation), the power supplied by the coziditioiier, as the power required by the system varies, or rather as tiie temperature of the air measured varies. The air flow rate can also be maintained at a minimum value, in the case of minimum power required by the system, to improve the sensitivity of the temperature sensors and/or move in any case the am in the room. In Figure 6 two vertical dashed Unes define the range of regulation; the weight of the range of regulation is irrelevant and depends on the control precision to be obtained. The temperature values, at which the various steps of the air flow rate are activated, can vary, provided the temperature gradient is gi-eater than the minimum allowed for proper functioning of displacement.
The advantages of the second embodiment arc similai" to those of the lirsl maimer, in particular, as can be seen in Fig, 7, the gradient is always m^iintained above the lower threshold for proper fimctioning of displacement. Moreover, as shovra in Figure 8, in the case of the flow rate variation taking place by variation of the revs of the fan, the consumption of the fan/fans decreases as the temperature of the ambient air decreases (therefore of the power required by the system). The reduction is different according to whether the fans are supplied with alternating current or with direct current.
In a third embodiment of the invention regulation by discrete steps is carried out both of the air flow rate and of the power. The embodiment is illustrated in Figs. 9-12.
The stepped regulation of the power is in actual fact a regulation of energy. In practice the conditioner is achiated and de-actuated but nevertheless, when actuated, always supplies 100% of the power. For example, to obtain 50% of the energy, actuation talces place for 30 minutes and de-actuation for a further 30 minutes.
In the case of one single regulation step, Fig. 9a, when the compressor is in function, it always supplies 100%i of the power. The air flow rate is equal to a fraction of the maximum, until the power required by the system approaches the maximum design power (or even exceeds it). In this case the air f!o\V rate rises to the design maximum.

In the cuKc of Fig. 9b, the power supplied by the conditioner is regulated in order Vo ibrni two steps. The air flow rate increases by discrete steps for values of power required by the .system which can vary as a ftmction of the percentage of regulation of the power supplied bythe conditioner.
A.S lor Die previous cases, in actual iacl regulation is performed on the basis of llie temperature of the air (deliver)", return or both) read by the sensors, as can be seen in the graph in Fig. 10. Within the range of regulation the air flow rate decreases by discrete steps. The width of the range of regulation is irrelevant and only depends on the control precision to be obtained. The temperature values at which the various steps of the air flow rate are activated can vary. The steps can be activated for lower values at the minimum temperature of tire range of regulation and deactivated also for values higher than the maximum temperature of the range of regulation.
The advantages are in particular, as mentioned in relation to the other embodiments, that the regulation method maintains the temperature gradient always above an established threshold value, aiid allows a considerable reduction in the consumption of the fans as the ambient temperature decreases, compared to the traditional regulation system. The reduction is more noticeable for fans supplied with direct current.
According to a fourth embodiment, modulating regulation of the air flow rate and regulation by discrete steps of the power are carried out, as illustrated in Fig. 13, as a function of the power required by the system and in Fig. 14 as a function of the temperattu-e of the air-(delivery, retum/Mnbient or both). Within the range of regulation, defined by the vertical dashed lines, the air flow rate decreases continuously with any trend as the temperature decreases, and the power supplied by the conditioner decreases by steps. the advantages are as mentioned with reference to the previous embodiments.


WE CLAIM:
1. Regulation method of displacement conditioners for maintaining the thermal gradient in the room be conditioned equal to or higher than the design valne as a function of the power required or bad requited, said method comprising regulation of the power supplied by the conditioner, further comprising combined regulation of the air flow rale supplied by the
2. Method according to claiml, wherein the reference parameter measured for regulation is the temperature of the delivery air and/or the return air or ambient air,
3. Method according to claim1, wherein the modulating regulation is carried out both of the
air flow rata and of the power of the condititioner.
4. Method according to claiml, wherein the modulating regulation of the power and
regulation by discrete steps of the airflow rate are carried out
5. Method according to claiml. wherein the regulation discrete steps is carried out both of
the air flaw rate and of the power of the conditioner.
6 Method according to clam 1, wherein the modulating regulation of the air flow rate and regulation by discrete steps of the power of the conditioner are carrried out
7. Ventilation conditioning system comprising combined regulation of the power supplied by the conditioner and of the air flow rale supplied by the cmditioner.

Documents:

1310-chenp-2004 abstract duplicate.pdf

1310-chenp-2004 abstract.pdf

1310-chenp-2004 claims duplicate.pdf

1310-chenp-2004 claims.pdf

1310-chenp-2004 correspondence others.pdf

1310-chenp-2004 correspondence po.pdf

1310-chenp-2004 description (complete) duplicate.pdf

1310-chenp-2004 description (complete).pdf

1310-chenp-2004 drawings duplicate.pdf

1310-chenp-2004 drawings.pdf

1310-chenp-2004 form-1.pdf

1310-chenp-2004 form-13.pdf

1310-chenp-2004 form-19.pdf

1310-chenp-2004 form-26.pdf

1310-chenp-2004 form-5.pdf

1310-chenp-2004 petition.pdf


Patent Number 202778
Indian Patent Application Number 1310/CHENP/2004
PG Journal Number 05/2007
Publication Date 02-Feb-2007
Grant Date 01-Nov-2006
Date of Filing 14-Jun-2004
Name of Patentee M/S. RC GROUP S.P.A.
Applicant Address Divisione RC Condizionatori, Via Roma, 5, I-27010 Valle Salimbene
Inventors:
# Inventor's Name Inventor's Address
1 TRECATE, Roberto [ Via Acqui, 12, I-27100 Pavia
PCT International Classification Number F24F 11/00
PCT International Application Number PCT/EP2002/014792
PCT International Filing date 2002-12-30
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 MI2002 A 000011 2002-01-08 Italy