DESC:FIELD OF THE INVENTION:
This invention relates to the field of instrumentation and electrical engineering.

Particularly, this invention relates to a system and method for maintaining humidity, with energy savings, in a defined environment

BACKGROUND OF THE INVENTION:
A defined environment such as an ‘operating theater (OT)’ (also known as an operating room (OR), operating suite, or operation suite) is a facility within a hospital where surgical operations are carried out in an aseptic environment. Operating rooms are generally windowless and feature controlled temperature and controlled humidity.

Relative Humidity (RH) is very important for Operation Theatres (OT) as higher or lower RH can increase possibility of infection or drying of wound. Level of RH may vary based on type of operation. For example, an eye surgery may require higher RH. But for given operation it is necessary to keep RH within plus minus 5%.

Similarly required OT room temperature also varies based on type of surgery and usually vary from 18 Deg C to 24 DegC. For a given type of operation plus minus 1 Deg C is desired.

According to published material, in the United States, an air temperature of 70 to 75°F (21 to 24°C) with 20 to 60% relative humidity, preferably 55%, provides a compromise between the requirements of the patients and those of the operators. In Britain, a temperature of 65 to 70°F (18 to 21°C) and a relative humidity of 50% is “well tolerated for many hours”. In the U.S.S.R., air-conditioning should provide in summer an air temperature of 68 to 72·5°F (20 to 22°C) and in winter 66 to 68°F (19 to 20°C) with a relative humidity of 55%

Usually, refrigeration peak load for OT varies from minimum 3 TR for a small OT to say 10 TR for a large OT. For the purpose of simplicity, one can consider typical OT having peak load as 6 TR. Two coils and condensing units each of 3 TR are considered. Though peak load is 6 TR, actual load, at any given time, may vary – say, from 2 TR to 6 TR. This is due to one, or more, of following reasons:
1- Ambient temperatures are lower;
2- Number of equipment used in OT depends on type of operation - for certain operations, high heat generation equipment are used while for some, negligible heat generation equipment are used;
3- Required temperature may vary between 18 Deg C to 24 Deg C - Peak load will be for 18 Deg C.

There is a need for a system and method to alleviate problems of the prior art.

Furthermore, it was observed, by the inventors, that most of OTs temperature requirement is easily met. But, more often, very high humidity fluctuations are encountered.

FIGURE 1 shows one of such scenarios, of the prior art, where most of OTs temperature requirement is easily met but RH is not met.

Data logger measuring temperature and humidity was placed in an OT and graph was drawn from data collected. RH% shot up over 80% and then dropped below 50%.

Even though NABH specified wide range of RH% it is better to maintain within 40 to 60% at all the time. United States Environmental Protection Agency (EPA) explains such a requirement with graph given in FIGURE 2.

FIGURE 2 illustrates EPA Recommended RH for Infection control.

ASHRAE also provides sho regarding optimum relative humidity for minimizing adverse health effects. From the figure it is observed that 40 to 60 % RH% is optimum for health.

FIGURE 3 illustrates optimum relative humidity for minimizing adverse health effects (ASHRAE).

Since many hospitals want various types of operations to be done in the same OT, set point requirement changes right from 16 Deg C to 24 Deg C. However, it is not possible to get 16 Deg C and say 50% RH using chilled water. A DX coil is must for such low temperature and RH requirements. Cooling load for OT seldom crosses 10 TR. Hence, most popular choice is air cooled condensing unit and DX cooling coil with Thermostatic expansion valve. If a single coil and condensing unit is provided problem becomes worse. Suppose, refrigeration capacity provided on peak load is 8 TR and at time load is only 4 - 6 TR. Compressor of condensing unit will cut Off and ON based on room temperature. When compressor is operational, it provides cold refrigerant to the coil; coil surface is cold and air flowing over the coil gets dehumidified. Most water drips on to a drain tray. But, some sticks to coil surface which makes coil wet. Now, when compressor cuts OFF on OT temperature, refrigerant flow to coil stops. Coil can no longer hold moisture stuck on it. Air flowing over the coil is unsaturated and it picks up this additional moisture and delivers to room. Thus, coil not only stops its dehumidification function, but gets converted into humidifying function for a short time. This causes RH to shoot up, abruptly; this is undesirable. When compressor restarts, it quickly drops back to normal. FIGURE 1 shows such phenomenon.

FIGURE 4 shows demonstration results conducted by Henderson in 1990.

Prior art citation KHATTAR et al. (1985) and prior art citation Henderson and Rengarajan (1996) have explained and demonstrated this phenomenon very well.

There is a need for a solution towards the aforementioned problems.

There were many plausible solutions, as discussed below:
SOLUTION 1: providing more than one coil and compressor. If 8 TR capacity is to be provided, then, as a solution, provide two coils of 4 TR placed one above other. As long as load is more than 4 TR, one coil will act as a dehumidifying coil and the other coil will toggle between humidifying coil and a de-humidifying coil when compressor is OFF and ON respectively. Moisture passing quantity will reduce and RH fluctuations will reduce to some extent. It should be noted that when one compressor is OFF, coil will, for some time, humidify the room and remaining time it will stop dehumidifying letting some moisture form return plus fresh air entering the OT.

SOLUTION 2: providing an intertwined coil. In this case, problem will further reduce but it is still will far from getting solved.

SOLUTION 3: A good solution can be achieved only if it is ensured that at all loads no compressor is shut off and refrigerant is always flowing through all the coils. There are various ways this can be achieved; however, energy consumption is high.

SOLUTION 3a: One of the more obvious methods was using VRF. A single VRF outdoor unit was connected to a single coil. However, the inventors could not get good results as turn down ratio of VRF compressor was not good and many times VRF compressor became OFF and problem persisted.

SOLUTION 3b: Provide additional heaters: the inventors provided extra capacity heaters. For example, for 6 TR (3 * 2 TR), the inventors provided heaters to the tune of 4 TR (14 KW). As the set point temperature gets achieved before compressor getting OFF, PLC orders to activate heater bank to required extent so that OT temperature never falls to compressor OFF set point. However, a problem with this solution is that electrical consumption increases drastically at part load (instead of going down).

In prior arts, it has been taught that for achieving low humidity reheat is required. But these books are talking about steady state conditions. In OTs we have seen such situations come rarely. Usually such reheat (if at all required) requirement is very small. But since it is mentioned in books that re-heaters reduce RH%, many A/C contractors installs large re-heaters. They operate whenever RH% goes up. Thus, when RH% shoots up due to OFF cycle of compressor, re-heaters are brought into picture. This makes RH% to oscillate up and down as shown in FIGURE 1. Correct way is heaters should be operated based on OT temperature so that Compressor will never get OFF on OT temperature. These way oscillations in RH% can be avoided.

FIGURE 4 shows demonstration results conducted by Henderson in 1990.

The inventors observed very seemingly paradoxical situation such that when set point was maintained at 22-23 Deg C re-heaters operate but when set point is set at 18 Deg C, they do not operate. At higher set point, capacity of condensing units becomes excessive making compressor cut off and FIGURE 4 phenomenon occurs. But, at 18 Deg C, capacity of refrigeration is just about sufficient and all compressors run continuously, hence re-heaters do not get activated.

SOLUTION 3c: In large hospitals, there may be chilled water plants of sizable capacity. In such a case, the inventors provided two coils in series. First chilled water coil followed by DX coil. Here minimum load is taken by DX COIL which never shuts off and capacity control is done by chilled water control valve. This way, chilled water coil dehumidification is variable but DX coil always dehumidifies air to required extent. This system is satisfactory from energy conservation point of view. However, most of the hospitals do not have such chilled water plant and solution has limited scope.

SOLUTION 3d: provide internal heater load. A parallel condenser coil is added as reheat coil to add the load. Whenever room temperature starts going below, say, 20 Deg C, part of hot gas from compressor goes to parallel condenser located on AHU. This extra load makes sure that at no time compressor gets OFF. A modulation scheme was employed to adjust required amount of bypassing the hot gas to AHU condenser instead of outside condenser. Though this appears simple, many precautions need to be taken and system becomes expensive as well as AHU size becomes bulky.

SOLUTION 3e: Conventional Hot gas bypass: When load reduces, suction pressure of compressor starts falling down. Diaphragm type hot gas valves are available which sense reduction in pressure and when pressure goes below spring-adjusted pressure, modulated quantity of hot gas starts flowing from compressor outlet to cooling coil as shown in FIGURE 5. This will add the load on coil and compressor switch off can be avoided. This system has indirect type of control on OT temperature. It does not sense OT temperature and supply hot gas to cooling coil to give extra load. But, it depends indirectly on the fact that, at lower loads, both suction pressure and OT temperature will start going down. Let us assume load goes down to 50%. From Q= U*A *LMTD equation LMTD will also reduce to half (Half LMTD).

FIGURE 5 illustrates a prior art hot gas bypass arrangement.

Where a=
Thus, at lower loads, coil becomes oversized and, hence, required evaporating temperature itself rises. Evaporating temperature and suction pressure are related by gas properties. Hence, required suction pressure to maintain OT temperature also changes. Still, it is observed that down to certain percentage load this system works. Main problem is encountered when set point need to be changed from say 18 Deg C to 22 Deg C. In such a case readjustment of spring pressure is required to be done manually (recalibration). This can be done only by expert technicians. Hence, scope of this system was found limited in OT air conditioning particularly where different types of operations are done.

From above discussions, it is clear that each of measures employed to stop compressor ON/OFF and, hence, to stop fluctuations in RH% has certain limitations.

Based on all above analyses, there is a need for a system which is cost effective, automatic, and simple; where no manual adjustment is required.

There is a need for a solution towards the aforementioned problems.

OBJECTS OF THE INVENTION:
An object of the invention is to maintain required humidity in a defined environment such as an Operating Theater using DX type system without using electrical heaters.

Another object of the invention is to save energy whilst maintaining required humidity in a defined environment such as an Operating Theater.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a system and method for maintaining humidity, with energy savings, in a defined environment, said system being a direct expansion system and comprising:
- an electronic expansion valve, configured with a stepper motor, said electronic expansion valve operating on said defined environment’s ambient temperature;
o said electronic expansion valve and said stepper motor, both being parallel, to a thermostatic expansion valve;
o said electronic expansion valve and said stepper motor, both being in series with an evaporator;
- a proportional controller configured to:
o obtain a signal, from a sensor, from said defined environment’s ambient temperature; and
o providing said obtained signal to said stepper motor, in response to said defined environment’s sensed ambient temperature in order to actuate opening / closing of said electronic expansion valve in order to feed hot gas from a compressor in order to introduce hot gas before said evaporator but after said thermostatic expansion valve.

In at least an embodiment, said system comprises a sensor to sense compressor suction pressure for purposes of safety.

In at least an embodiment, said stepper motor is connected to said electronic expansion valve in order to, in a stepless manner, open and / or close said valve such that room temperature is maintained in a desired / pre-configured band.

In at least an embodiment, said system’s hot gas bypass circuit is configured with:
- a hot gas line, being parallel to said condenser, and in line, before, said electronic expansion valve;
- said electronic expansion line and said stepper motor in line with said hot gas line; and
- said evaporator in line with said electronic expansion line and said stepper motor.

In at least an embodiment, said electronic expansion valve, in said hot gas bypass circuit, being configured to be modulated based on room temperature, said proportional controller being defined terms of threshold parameters, as a tolerance of a set point value, in order to
- open said valve, by a pre-defined portion, by sending a signal to said stepper motor, if said temperature breaches a first tolerance threshold value; and
- close said valve, by a pre-defined portion, by sending a signal to said stepper motor, if said temperature breaches a second tolerance threshold value;
o thereby, achieving modulation of said valve, by said stepper motor, in response to one or more signals received from said proportional controller, said modulation being varying degrees of opening and closing between a fully closed condition of said valve and a fully open condition of said valve.

In at least an embodiment, said system comprises a condensing unit coupled to said compressor configured to, always, compress same amount of gas thereby increasing evaporator load, with pre-defined range/s, and keeping said compressor, and said coupled condensing unit, always ON.

In at least an embodiment, said system comprises:
- a condensing unit coupled to said compressor;
- a receiver in line with said condenser; and
- said receiver in line with said thermostatic expansion valve.

In at least an embodiment, said system comprises:
- a condensing unit coupled to said compressor;
- a hot gas line parallel to said condenser; and
- said hot gas line located, in line, before said electronic expansion valve.

In at least an embodiment, said system comprising:
- a suction line which flows from said evaporator to said compressor.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:

FIGURE 1 shows one of such scenarios, of the prior art, where most of OTs temperature requirement is easily met but RH is not met;
FIGURE 2 illustrates EPA Recommended RH for Infection control;
FIGURE 3 illustrates optimum relative humidity for minimizing adverse health effects (ASHRAE);
FIGURE 4 shows demonstration results conducted by Henderson in 1990;
FIGURE 5 illustrates a prior art hot gas bypass arrangement.
FIGURES 8a and 8b show variation of OT temperature and RH with respect to time;
FIGURE 6 illustrates a bypass mechanism of the prior art;
FIGURE 7 illustrates a schematic diagram of the system of this invention;
FIGURE 7a illustrates a controller (40) which is a proportional controller used in conjunction with this invention’
FIGURES 8a illustrates a prior art’s hot gas bypass system which also maintains RH but set point change will require re-adjustment which also requires high skill;
FIGURES 8b illustrates this invention’s readings; at fixed set point, the system maintains RH and temperature very well;
FIGURES 8c illustrates this invention’s readings; even if set point is changed EEV Hot gas bypass will maintain RH automatically;
FIGURE 9a illustrates high energy consumption due to heaters for prior art system without any hot Gas Bypass; and
FIGURE 9b illustrates, according to this invention, that energy consumption remains almost same as no heaters are activated even though set point is changed.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Typically, refrigeration capacity is designed for peak load. At lower loads, temperature starts going below room temperature set point. In such cases, room thermostat switches off one of the two or more compressors. This leads to low temperature refrigerant not passing through cooling coil connected to the compressor that is switched off. Removal of moisture is done by cooling coil (as moisture is present in air passing over coil which condenses on the coil). When moisture is removed by the coil, most of the moisture drops down and the remainder sticks to a wall; making the coil wet with water. Since coil does not have refrigerant, coil can no longer hold the moisture. Air passing on such a coil will take away this moisture attached to coil and reach an Operating Theatre, or such defined environment; thereby, suddenly increasing Relative Humidity in Operating Theatre.

FIGURE 4 explains such phenomenon.
Thus, when one of the compressors shuts down, not only moisture will STOP CONDENSING on coil but moisture earlier condensed also will be added in the operating theatre. This will shoot relative humidity, in the operating theatre above 70%. Thus, to maintain relative humidity, at all times, it is important that all compressors need to run continuously.

Further field experience indicates that maintenance is greatly reduced if a compressor operates continuously as compared to frequent cycling (on and off); as electrical problems are minimized, compressor lubrication is improved, and refrigerant migration is avoided.

There are numerous ways of making sure that the compressor works continuously.

One of the ways to make sure than the compressor works continuously is described below:
Reduction of frequency of electrical supply provided to electrical motor. This is, perhaps, one of the more energy efficient ways as it reduces compressor power consumption and also does not add extra load like other options. However, oil return becomes very complex and methods to handle the same make capital cost very high.

One of the ways to make sure than the compressor works continuously is described below:
Adding of extra load by means of a heating coil or electrical heaters; if one provides additional 3.5 Kw of heater per TR of reduced load, compressor will never stop. But, if load becomes 3 TR instead of 6 TR, electrical heaters consumption becomes 11 KW. Since, most of the time, load is less than peak, continuous operation of heaters not only increase energy cost but also reduce life of heaters requiring replacements frequently

One of the ways to make sure than the compressor works continuously is described below:
Conventional hot gas bypass method: On single evaporator, close connected system; hot gas from compressor is introduced into an evaporator inlet immediately after an expansion valve. Distributors are available with side openings for hot gas inlet. Bypassing, at the evaporator inlet, has an effect of creating artificial cooling load. Since, a regular system thermostatic expansion valve meters its feed, as required, to maintain its superheat setting, refrigerant gas returns to the compressor, at normal operating temperatures, and no motor heating problem is involved. High velocities are maintained in the evaporator; so, oil return is aided. Because of these advantages, this type of control is relatively simpler, relatively inexpensive, and a relatively satisfactory bypass system.

FIGURE 6 illustrates a bypass mechanism of the prior art.

Further, in this system, a hot gas bypass valve (11) senses evaporator pressure. When load is less than condensing unit capacity, refrigerant temperature (and, hence, corresponding saturation pressure) in coil starts going down. When hot gas bypass valve senses such reduction in pressure, it opens, in modulation, and allows, to pass, sufficient amount of hot gas to the coil so that coil pressure is maintained at set pressure. Thus, in this type of system, by means of a self-adjusting screw, required pressure in the evaporator needs to be set by an expert mechanic. Nowadays, an electronic expansion valve also does the same function to maintain evaporator or coil pressure

However, in this method when an operating room theatre’s temperature set point is increased due to type of operation, required pressure in coil to maintain room temperature also increases. It is not possible for a hospital operator to know new settings. Similar phenomenon may take place when load is lower than designed capacity due to lower ambient temperatures or working of lesser electrical equipment. Thus, unless a hospital operator changes set pressure of bypass valve manually, continuous operation of all compressors cannot be ensured; thereby, again, causing sudden increase in relative humidity (and, thus, not addressing the problem at all).

In order to alleviate all of these concerns, a system and method in accordance with the current invention is proposed.

According to this invention, there is provided a system and method for maintaining humidity, with energy savings, in a defined environment.

FIGURE 7 illustrates a schematic diagram of the system of this invention.

In at least an embodiment of this invention, an electronic expansion valve (10) configured with a stepper motor (20) is provided, parallel, to a thermostatic expansion valve (12), and in series with an evaporator (14). Instead of sensing evaporator pressure and operating a hot gas bypass valve (11, Figure 2) (which was used in prior art systems), the current system is configured to use another type of valve (i.e. the Electronic expansion valve) which operates on room (30) / ambient temperature (defined environment’s temperature). When load reduces, room temperature starts falling down as refrigeration capacity is more than load. To do this, the electronic expansion valve (10), without its standard controller, is to be used. In prior art systems, such valves are normally used with a dedicated and exclusive controller (which is supplied with the valve) either for maintaining superheat; thereby, replacing thermostatic expansion valve or hot gas bypass valve. Here, again, if a hot gas bypass valve is used, according to prior art, evaporator (14) pressure is sensed and a dedicated controller is preprogrammed for opening and closing the hot gas bypass valve with a stepper motor to maintain evaporator pressure constant.
In at least an embodiment, the system comprises a controller (40) which obtains a signal (18), from a sensor (16), from room (30) temperature and based on room temperature, the controller (40) gives the signal (18) to the stepper motor (20)in order to actuate opening / closing of the electronic expansion valve (10), sufficiently, to feed hot gas from a compressor (50) in order to introduce hot gas before the evaporator (14) but after the thermostatic expansion valve (12). When more hot gas is introduced, some of the liquid refrigerant going to the evaporator (14) will be turned to vapour after mixing, liquid vapour mixer is fed to evaporator. A conventional (prior art) controller that is, typically, supplied with an electronic expansion valve senses refrigerant pressure and temperature leaving the evaporator to give signal for modulating the electronic expansion valve. The system, of this invention, aims to measure room temperature in order to modulate the electronic expansion valve; hence, the use of this conventional (prior art) controller is not possible to. Therefore, this invention’s controller provides a logic (built in PLC/ microprocessor) so that the electronic expansion valve, in the hot gas bypass circuit, will modulate based on room temperature and also monitor compressor suction pressure for purposes of safety.

Typically, a stepper motor is a motor that angularly displaces in steps; e.g. for every signal, the motor angularly displaces 1 degree angle out of 360 degrees. An electronic expansion valve is used for refrigerant control to evaporator in cooling. Stepper motor moves the a valve up and down in order to control quantity of refrigerant from inlet to outlet. Each step can be in defined in terms of percentages i.e. 25%, 50%, 75%, 100%, or the like. However, if it opens every 0.5%, it is practically stepless; which is what is achieved by the controller of this invention.

FIGURE 7a illustrates a controller (40) which is a proportional controller used in conjunction with this invention.
Reference numeral 40a refers to set point temperature as a first input provided to a comparator (40b).
Reference numeral 40c refers to set point temperature as a second input provided to a comparator (40b), the second input being feedback signal obtained from a sensor (16).
Block 10 refers to electronic expansion valve and its modulation as a response to comparator (40b) output.
Block 16 refers to feedback obtained from temperature sensor (16).
Reference numeral 40d refers to output which is amount of hot gas released to evaporator coil.

Since lesser amount of cold liquid is now fed to the evaporator (14), the evaporator’s (14) capacity is lower and, hence, room (30) temperature which was, earlier, falling down will, now, rise. The controller (40), of this invention, is made to open the electronic expansion valve (10) with the stepper motor (20) in such a way that room (30) temperature is maintained in a desired / pre-configured band.

In this way, condensing unit’s (60) compressor always compresses same amount of gas but evaporator (14) capacity being reduced compressor will never shutoff thereby keeping condensing unit (60) always ON. Since condensing unit (60) is always running and only required amount of cold refrigerant liquid is fed to the evaporator (14), evaporator (14) coil withholds moisture attached to it. This ensures that no extra moisture is fed to the room (30) and, therefore, room humidity is maintained.

Reference numeral 22 refers to a receiver in line with the condenser (60) and the thermostatic expansion valve (12).
Reference numeral 24 refers to a hot gas line parallel to the condenser (60) and in line, before, the electronic expansion valve (10).
Reference numeral 26 refers to a suction line which flows from the evaporator (14) to the compressor (50).

According to a non-limiting exemplary embodiment, a set up was established for the aforementioned invention. Continuous readings were taken by a data logger (frequency every 30 Secs) and graphs were plotted. For every situation, ambient temperature and RH% were also recorded. It was observed that whenever set point was changed or ambient conditions varied drastically (DB 40 Deg C to 23 Deg C), valve adjustment was required for conventional HGB or hand valve. However, EEV modulated from 0-100% based on OT temperature and no manual intervention was required; thus proving the TECHNICAL ADVANTAGES of the system of this invention.

FIGURES 8a illustrates a prior art’s hot gas bypass system which also maintains RH but set point change will require re-adjustment which also requires high skill.

FIGURES 8b illustrates this invention’s readings; at fixed set point, the system maintains RH and temperature very well.

FIGURES 8c illustrates this invention’s readings; even if set point is changed EEV Hot gas bypass will maintain RH automatically.

FIGURE 9a illustrates high energy consumption due to heaters for prior art system without any hot Gas Bypass.
FIGURE 9b illustrates, according to this invention, that energy consumption remains almost same as no heaters are activated even though set point is changed.

Because of this invention, it was observed that:
1. Heaters do provide RH control without oscillations in RH%, provided that they operate through PLC to avoid OFF cycling of compressor. Without PLC, if heaters are operated, large fluctuations in RH% cannot be avoided; they are also energy guzzlers;
2. EEV provide good control on RH by avoiding off-cycling of compressor and stable RH%. Using EEVs, tuning of valves is also not required (which was the case in prior arts) to change set point;
3. Reheat was not required in this setup; even if required, they do not exceed 3KW for an OT unlike prior art's 10KW requirement (where hot gas method is not used); this makes the system, of this invention, environment friendly.

The system, of this invention, can be employed anywhere where absolute control of RH% and temperature is required with DX system.

The TECHNICAL ADVANCEMENT of this invention lies in a system and method which provides a continuously monitoring, continuously adjustable temperature and humidity maintaining system; without switching off compressor(s) and without using electrical heaters to provide additional load.

While this detailed description has disclosed certain specific embodiments for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

,CLAIMS:WE CLAIM,

1. A system and method for maintaining humidity, with energy savings, in a defined environment, said system being a direct expansion system and comprising:
- an electronic expansion valve (10), configured with a stepper motor (20), said electronic expansion valve (10) operating on said defined environment’s (30) ambient temperature;
o said electronic expansion valve (10) and said stepper motor (20), both being parallel, to a thermostatic expansion valve (12);
o said electronic expansion valve (10) and said stepper motor (20), both being in series with an evaporator (14);
- a proportional controller (40) configured to:
o obtain a signal (18), from a sensor (16), from said defined environment’s (30) ambient temperature; and
o providing said obtained signal (18) to said stepper motor (20), in response to said defined environment’s (30) sensed ambient temperature in order to actuate opening / closing of said electronic expansion valve (10) in order to feed hot gas from a compressor (50) in order to introduce hot gas before said evaporator (14) but after said thermostatic expansion valve (12).

2. The system as claimed in claim 1 wherein, said system comprising a sensor to sense compressor suction pressure for purposes of safety.

3. The system as claimed in claim 1 wherein, said stepper motor (20) being connected to said electronic expansion valve (10) in order to, in a stepless manner, open and / or close said valve (10) such that room (30) temperature is maintained in a desired / pre-configured band.

4. The system as claimed in claim 1 wherein, said system’s hot gas bypass circuit being configured with:
- a hot gas line (24), being parallel to said condenser (60), and in line, before, said electronic expansion valve (10);
- said electronic expansion line (10) and said stepper motor (20) in line with said hot gas line (24); and
- said evaporator (14) in line with said electronic expansion line (10) and said stepper motor (20).

5. The system as claimed in claim 1 wherein, said electronic expansion valve (10), in said hot gas bypass circuit, being configured to be modulated based on room temperature, said proportional controller (40) being defined terms of threshold parameters, as a tolerance of a set point value, in order to
- open said valve (10), by a pre-defined portion, by sending a signal to said stepper motor (20), if said temperature breaches a first tolerance threshold value; and
- close said valve (10), by a pre-defined portion, by sending a signal to said stepper motor (20), if said temperature breaches a second tolerance threshold value;
o thereby, achieving modulation of said valve (10), by said stepper motor (20), in response to one or more signals received from said proportional controller (40), said modulation being varying degrees of opening and closing between a fully closed condition of said valve (10) and a fully open condition of said valve (10).

6. The system as claimed in claim 1 wherein, said system comprising a condensing unit (60) coupled to said compressor (50) configured to, always, compress same amount of gas thereby increasing evaporator (14) load and keeping said compressor (50), and said coupled condensing unit (60), always ON.

7. The system as claimed in claim 1 wherein, said system comprising:
- a condensing unit (60) coupled to said compressor (50);
- a receiver (22) in line with said condenser (60); and
- said receiver (22) in line with said thermostatic expansion valve (12).

8. The system as claimed in claim 1 wherein, said system comprising:
- a condensing unit (60) coupled to said compressor (50);
- a hot gas line (24) parallel to said condenser (60); and
- said hot gas line (24) located, in line, before said electronic expansion valve (10).

9. The system as claimed in claim 1 wherein, said system comprising:
- a suction line (26) which flows from said evaporator (14) to said compressor (50).

Dated this 08th day of August, 2022

CHIRAG TANNA
of INK IDÉE
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA - 1785