LEWIS, Craig (c/ Sedac Energy Management Pty Ltd, 14 Centofanti PlaceThomastown, VIC 3074, AU)
| Claims 1. An evaporator saver for a heat exchange refrigeration systems including a cooled chamber; a compressor outside the cooled chamber; a condenser outside the cooled chamber; an evaporator inside the cooled chamber; an evaporator fan or fans inside the cooled chamber; and refrigerant feeding along refrigerant lines between the various components in the system to provide a refrigeration effect, wherein the evaporator saver lowers energy use in the heat exchange refrigeration system by lowering fan usage at assessed different cooling modes while maintaining cooling effectiveness. 2. An evaporator saver according to claim 1 wherein the fan usage can be reduced to 30% or greater of the fan speed capacity at times of various component modes of operation. An evaporator saver according to claim 1 wherein the fan usage can be reduced to 50% or less of the tan speed capacity at times of various component modes of operation. An evaporator saver according to claim 1 wherein the fan usage can be reduced to substantially within the effective range of 30% to 50% of the fan speed capacity at times of various component modes of operation. An evaporator saver for a heat exchange refrigeration systems according to any one of the preceding claims wherein the heat exchange refrigeration system is usually a walk-in refrigerated coolroom operating substantially under 4 degrees Celsius. An evaporator saver for a heat exchange refrigeration systems according to claim 4 wherein the cooling modes can include a cooling mode, a non-cooling mode, a defrost mode, and other modes. An evaporator saver according to any one of the preceding claims having an evaporator fan control means for monitoring a cooling or non-cooling status of the system, including the steps of: a. the control means sets an energy saving operational speed for the evaporator fan based on the system cooling or not cooling. b. If the cooling system is detected as on, the evaporator fan controller does not limit the evaporator fan which continues to operate at a 100% speed, c. If the cooling system is detected as off, the evaporator fan controller decreases the operational speed of the evaporator fan to a speed no ' lower than 30% of the fan speed capacity, thereby decreasing evaporator fan produced heat, resulting in an overall decreased energy requirement for the heat exchange refrigeration system. An evaporator saver according to any one of the preceding claims wherein due to operative link between cycling operation of the compressor and evaporator fan speed operation there is a decrease in the cycling operation of the compressor when decrease in evaporator fan speed operation resulting in less compressor usage. An evaporator saver according to any one of the preceding claims including sensors such as ice detectors on the coil so as to override low fan speed and effect speed up of evaporator fan to stop icing. 10. A means of determining reduced capacity of compressors in a heat exchange refrigeration system Including the steps of: a. providing a heat exchange refrigeration system having a cooled chamber; a compressor outside the cooled chamber; a condenser outside the cooled chamber; an evaporator inside the cooled chamber; an evaporator fan or fans Inside the cooled chamber; and refrigerant feeding along refrigerant lines between the various components in the system to provide a refrigeration effect b. providing an operative link between cycling operation of the compressor and evaporator fan speed operation; c. determining times of mode of operation for providing lower evaporator fan speed operation which thereby provides decrease In compressor cycling; and d. determining lower capacity of required compressors over a full operation mode using fluctuation in evaporator fan speed operation in various component times of mode of operation. 11. A means of determining reduced capacity of compressors in a heal exchange refrigeration system according to claim 10 wherein due to operative link between cycling operation of the compressor and evaporator fan speed operation there is a decrease in the cycling operation of the compressor when decrease in evaporator fan speed operation resulting in less compressor usage. 12. A means of determining reduced capacity of compressors in a heat exchange refrigeration system according to claim 10 or 11 wherein a capacitance can be determined such that the design can make use of lower capacitance and minimise equipment required to provide the same effective cooling. 13. A means of determining reduced capacity of compressors in a heat exchange refrigeration system according to claim 10, 11 or 12 wherein In use a control box is provided containing a fan speed controller and a solid state relay which reduces evaporator fan speed, while cool room Is at set point temperature or in defrosts cycle, this in turn reduces refrigeration energy consumption to run, reducing airflow while a room is at a set temperature will also minimize dehydration of stock and prolong life of product, also reducing compressor run times. 14. A means of determining reduced capacity of compressors In a heat exchange refrigeration system according to any one of claims 10 to 13 wherein the system is connected to a bank of evaporator fans 15. A means of determining reduced capacity of compressors in a heat exchange refrigeration system according to any one of claims 10 to 14 wherein containing two supplies one from the fan and a second tram the temperature control (Solenoid) such that when the cool room is in cooling mode the fan speed is at 00%, and when the room reaches the required set point or is in a defrost mode then the fan speed is preset to operate between 30% - 50%. 16. An evaporator saver substantially as hereinbefore described with reference to the drawings. 17. A means of determining reduced capacity of compressors in a heat exchange refrigeration system substantially as hereinbefore described with reference to the drawings. |
Field of the Invention
The present invention relates to an evaporator saver and more particularly, to saving energy and capacity of a heat exchange refrigeration system such, as used in walk-in coolrooms.
Background to the Invention
It is an object of the present invention to provide an improved heal exchange refrigeration system and parts therefore that assists in reducing the overall energy consumption of cool rooms.
Summary of the Invention
According to one aspect, the present invention provides an evaporator saver that lowers energy use in a heat exchange refrigeration system by lowering fan usage at assessed different cooling modes while maintaining cooling effectiveness
An evaporator saver wherein the fan usage can be reduced to 30% or greater of the fan speed capacity at times of various component modes of operation.
An evaporator saver wherein the fan usage can be reduced to 50% or less of the fan speed capacity at limes of various component modes of operation.
However a particular unexpected benefit arises if the evaporator saver has the fan usage can be reduced to substantially within the effective range of 30% to 50% of the fan speed capacity at times of various component modes of operation.
The heat exchange refrigeration system is usually a walk-in refrigerated coolroom operating under 4 degrees Celsius, but may extend to other similar systems. Such heat exchange refrigeration systems include a cooled chamber; a compressor outside the cooled chamber; a condenser outside the cooled chamber; an evaporator inside the cooled chamber; an evaporator fan or fans inside the cooled chamber; and refrigerant feeding along refrigerant lines between the various components in the system to provide a refrigeration effect.
The cooling modes can include a cooling mode, a non-cooling mode, a defrost mode, and other modes. Generally, the evaporator saver apparatus has an evaporator fan control means for monitoring a cooling or non-cooling status of the system, whereby the control means sets an energy saving operational speed for the evaporator fan based on the system cooling or not cooling. It the cooling system is detected as on, the evaporator fan controller does not limit the evaporator fan which continues to operate at a 100% speed. If the cooling system is detected as off, the evaporator fan controller decreases the operational speed of the evaporator fan to a speed no lower than 30% of the fan speed capacity, thereby decreasing evaporator fan produced hoat, resulting in an overall decreased energy requirement for the heat exchange refrigeration system. Similarly due to operative link between cycling operation of the compressor and evaporator fan speed operation there Is a decrease in the cycling operation of the compressor resulting in less compressor usage.
The system can include sensors such as ice detectors on the coil so as to override low fan speed and effect speed up of evaporator fan to stop icing.
The evaporator saver, due to operative link between cycling operation of the compressor and evaporator fan speed operation, provides a decrease in the cycling operation of the compressor when decrease in evaporator fan speed operation resulting in (ess compressor usage.
In another aspect of the invention there is provided a means of determining reduced capacity of compressors in a heat exchange refrigeration system Including the steps of:
providing a heat exchange refrigeration system having a cooled chamber; a compressor outside the cooled chamber; a condenser outside the cooled chamber; an evaporator inside the cooled chamber.; an evaporator fan or fans inside the cooled chamber; and refrigerant feeding along refrigerant lines between the various components in the system to provide a ' refrigeration effect
providing an operative link between cycling operation of the compressor and evaporator fan speed operation;
determining times of mode of operation for providing lower evaporator fan speed operation which thereby provides decrease in compressor cycling; and
determining lower capacity of required compressors over a Ml operation mode using fluctuation in evaporator fan speed operation in various component times of mode of operation. It can be seen that by use of this method a capacitance can be determined such lhat the design can make use of lower capacitance and minimise equipment required to provide the same effective cooling. In use a control box is provided containing a fan speed controller and a solid state relay which reduces evaporator fan speed, while cool room is at set point temperature or in defrosts cycle. This in turn reduces refrigeration energy consumption to run. Reducing airflow while a room is at a set temperature will also minimize dehydration of stock and prolong life of product, also reducing compressor run times.
A licensed electrician must wire the application to a bank of evaporator fans. It contains two supplies 1 from the fan and 2 from the temperature control (Solenoid). When the cool room is in cooling mode the fan speed is at 100%. When the room reaches the required set point or is in a defrost mode then the fan speed is preset between 30% - 50%.
Other applications can handle larger loads, different voltages. 3 phases and incorporate delay timers.
We have developed a Fan Speed Controller which reduces the fan speed of evaporators on demand.
Evaporator Savings
This controller turns the fan to 100% when cooling and when the room reaches its set point or defrost times it reduces the speed to 30% affectively saving 70% of the fan load.
Compressor Savings
As the evaporator uses les9 heat and the room requires less cooling compressors run time is reduced which also prolongs the life of the compressor.
Product Savings
When the room reaches its required temperature the air movement is reduced which decreases the dehydration of product and extends shelf life of the products.
We also have different models which adapt to specific installations. Our products cover different fan loads along with 3 phase fans,
• EC Motors
. VSD's Brief Description of the Drawings
A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1a and 1b is an example ot componentry of an evaporator saver in accordance with an embodiment of the invention;
Figure 1c is a test result of one embodiment of the invention illustrating current usage which increases after a changeover;
Figure Id is a further test result in accordance with the test in Figure 1C illustrating the use of a coolroom fan at 30% and 100%;
Figure 2 is a diagrammatic circuit layout of an evaporator saver in accordance with an embodiment of the invention;
Figures 3 to 8 are results of physically testing the application and gaining physical data proving the functionality of an evaporator saver in accordance with an embodiment of the invention;
Figure 9 is a photographic image of the componentry of an evaporator saver in accordance with a further embodiment of the invention;
Figure 10 is a diagrammatic image of the wiring illustrating the connection for remote speed limiter;
Figures 11A to 11C are results of testing (Test 1} of the invention iflustrating the behaviour of the unit over a time period spanning 1 August 2010 to 18 October 2010;
Figures 12A to 12C are results of testing the invention to illustrate the compression behaviour at 50%, 40% and 100%, In accordance with the parameters of Test 1;
Figures 13A to 13E is a test result of the Invention (Test 2), illustrating the result of the invention over a run time of over 40 hours, refrigeration cycles from 312 and to determine average temperature maintained
Figures 14A to 14E are results of further testing of the invention, in accordance with the parameters of Test 2, to illustrate the rack and compressor behaviour including temperature and pressure cycles;
Description of a Preferred Embodiment of the Invention
Referring to Figure 1 there is shown the component parts of a heat exchange refrigeration systems including a cooled chamber; a compressor outside the cooled chamber, a condenser outside the cooled chamber; an evaporator inside the cooled chamber; an evaporator fan or fans inside the cooled chamber; and refrigerant feeding atong refrigerant lines between the various components in the system to provide a refrigeration effect.
Figure 2 details the control device in combination with the component parts of a heat exchange refrigeration systems for a coolroom.
Figure 3 is an operative use of an evaporator fan at 100% of the fan speed capacity with temperature shown in vertical scale and time across horizontal scale and showing ambient temperature variation at the top and compressor cycling at the bottom. The resultant temperature of coolroom is shown therebetween with fluctuations matching compressor cycling but the range of coolroom temperature remaining between about 1 and 3 degrees. Figure 4 shows some statistical figures corresponding to 100% operation. In particular Figures 3 and 4 show 126 cycles in 12 hour period at 100% fan speed.
Figure 5 is an operative use of an evaporator fan at 30% of the fan speed capacity with temperature shown in vertical scale and time across horizontal scale and showing ambient temperature variation at the top and compressor cycling at the bottom. The resultant temperature of coolroom is shown therebetween with fluctuations matching compressor cycling but the range of coolroom temperature remaining between about 1 and 3 degrees. Figure 6 shows some statistical figures corresponding to 30% operation. In particular Figures 3 and 4 show 86 cycles in 12 hour period at 30% fan speed. Figure 7 shows a comparison of 30% to 100% over time and shown particularly by the change of compressor cycling at the bottom but still providing an operative effective cooling that remains within about 1.4 to 3 degrees. Similarly Figure 8 shows the power comparison Of 30% to 1 0% over time and shown particularly by the change of compressor cycling at the bottom
Looking at the structure in more detail, the Invention therefore provides for;
a) Improved energy efficiency of HVAC refrigeration condenser, fans, fan coil units, air conditioner fans;
b) Remote control. 240 VAC remote switching of fan from LOW/HIGH c) Independent Fully Isolated remote control independent of fan circuit.
d) Preset speed/power adjusts low speed from approximately 20 to 100%. e) Fully Solid State no relays to wear out. f) Universal power limiting for all resistive and most inductive loads.
g) Suitable for PSC, shaded pole and universal motors. Electronic speed control for fans/blowers/pump where the load torque varies with speed.
h) 2 and 3 wire control selectable - allows control of a wide variety of PSC motors in many different fan applications
i) RoHS and CTick compliant.
Further specifications of the invention are identified in the table below.
The invention further provides guidelines for installing the evaporator saver. This will now be detailed as follows:
The evaporator saver varies available power to the load using phase angle conduction control. As the conduction angle is reduced the power to the load is reduced. This reduction is accompanied by a reduction in the AC voltage across the load and can be used as an indicator of the speed/power increase. The MSL limiter is actuated via a fully isolated control signal 2 0 VAC at very low current from controlling 3
devices such as refrigeration condenser solenoid valves, control relays, switches or other mechanisms. The control signal is phase independent.
With regard to motor considerations: Phase angle conduction control is suitable for most electric motors of the PSC, shaded pole or universal AC/DC type. Universal and shaded pole motors are usually speed controllable irrespective of their load characteristics. PSC motors with a permanent capacitor connected between the main and aux windings are only speed controllable if the load torque characteristics change (increase) with speed. Fans and centrifugal pumps are ideal loads but high starting torque loads such as compressors, lathes, pedestal drills or loads whose toque does not change with speed, are not. Motors with starting relays or centrifugal switches are not suitable for speed control. Inefficient and poorly matched motor/load combinations are more difficult to speed control particularly where the motor is sized larger than the load requires.
The evaporative saver can be connected to motors in two different configurations.
For transformer, resistive loads and shaded pole or universal (brush) motors, the2- wire connection should be used. The 2 wires are simply input and output with neutral and earth being ancillary connections.
For PSC(Capacitor) motors, as can be seen from Figure 10, there are two ways in which the motor may be wired. Generally the 2-wire is simplest and can be used for smaller motors <120W output power. The 3-wire configuration involves connecting the main and auxiliary windings of the motor to different parts of the MSG 1200 controller. Three wires are thus involved-input, main output and auxiliary output. The 3-wire is slightly more complex but for some motors offers better speed, control over the range, higher efficiency and lower motor temperature. The 3-wire is highly recommended for all PSC motors. The 3-wire must be used for PSC motors >300W.
Larger motors configured as 2-wire may run hotter and control may be less linear.
The SC1200 can be used with more than 1 motor or load (all connected similarly in parallel) provided the maximum current is not exceeded. LOW/HIGH control is configurable either as 2 or 3 wire BUT ON/OFF control is only for 2 wire.
The invention further provides for overload protection. The evaporative separator, including the series controllers, limiters and VSD's are adequately rated for motor starting and a generous short term overload margin is provided The overload protection can be used to protect the motor and the evaporative saver in accordance with electrical wiring regulations. As a guide, fit a magnetic circuit breaker rated at 1.25X the load max nameplate current but = to or iess than the maximum controHer/limiter rated current. If a fuse (Slow blow) or manually resetabie thermal overload (ThOL) is to be used, rate it at the maximum motor name plate current. For thermal overloads, consideration may need to be given to ambient operating temperature to ensure adequate protection and/or spurious tripping. It would however not be recommended that automatically resetting thermal overloads fitted to some motors be relied upon for sole protection of the motor/control system. With regard to earthing: the controller must be installed In accordance with AS3000 which requires that the case of the controller be adequately earthed.
With regard to control input: a separate 240 VAC control signal actuates the evaporator saver and may be from a different active phase or supply to that supplying the fan/controller. For the LOW/HIGH version-no control signal (low speed) the evaporative saver output is adjusted with the low preset adjusted. When the control signal is applied, the unit will go to maximum speed and on the dual version the high speed is also preset adjustable. The control input is fully isolated and draws approximately 10ma.
The evaporative saver further provides for a speed adjustment. A recessed screwdriver preset trim adjuster is located on the side of the casing. This adjusts the speed level on a preset basis as per the control version. Turning the trim pot anti ¬ clockwise will reduce the speed setting and vice versa. The speed is set after the controller has been actuated by carefully adjusting the trim pot until the required speed is reached. It must be ensured that the lower speed is selected to allow sufficient air flow across the motor to prevent it from overheating. The user must be careful not to force the trim pot adjuster beyond its stops or push too hard. Two potentiometers are supplied on dual adjustment versions with the lower potentiometer being the high speed adjustment.
With regard to electromagnetic compliance and earthing: when properly installed the evaporative separator range of controilers limiters meets the electromagnetic compliance (EMC) requirements Of Australia and New Zealand. Compliance requires that the conductor between the controller and the load or motor main winding be screened (shielded), and that the screen be earthed at one point. If more convenient, the screening may be accomplished by enclosing all the cables between the controller and load motor in an earthed screen. If the motor load and controller are housed together in a common metal chassis which is earthed, then this may be sufficient screening. The cross-sectional area of screening on a single cable is not normally sufficient to be used as an earth conductor.
Test examples
EVAP.SAVER ESMT-1-6A
1. The standard cool room version, model no ES T-1-6A is a solid state, relay based fully adjustable speed controller. It is fully compliant with NATA inc. C-tick certification, has no moving parts and Is designed and manufactured locally in Australia. It is the base model of SEDAC's range of speed controllers designed for medium and low temperature cool rooms with fan banks of no more than 5 amps total load. For larger cool rooms the ESMT-1-2QA is recommended. It is able to adapt to different refrigerants including R404, R134 and C02 among others.
2. its operation is based on the following method; when the cool room reaches its set-point
Temperature, the speed controller will receive a Ov signal from the solenoid, valve, compressor or relative output (ie; off cycle). At this point the speed controller will lower the fan speed to approximately 40%. This will boil off whatever liquid remains within the evaporator, whilst still moving limited air across the evaporator fins so as not to ice up. The ballast (or stock) within the cool room wiil then remain at its temperature for a longer period, as there is a reduced amount of ambient airflow around the room.
3. When the cool room rises in temperature above its differential set-point and calls for cooling, the speed controller will automatically and instantly revert the fan speed to 100% for the cooling period.
The following tests, illustrated in Figures 11 to 14, identify successful testing of the invention in major supermarket chains, all having different plant designs. As can be seen in the accompanying figures, such testing has identified the behavior of the invention on both smaller and larger installations allowing the Inventor to identify the selection of operation. Trial Site 1
Self contained refrigeration system
Site Description · Liquor Land
Plant design - 1 x liquor cool room containing 4 x refrigerated evaporators controlled by a self contained unit mounted on the roof.
Monitored Power consumption of the entire plant. As plant is quite small we were able to identify Evaporator power consumption & compressor cycles. The compressor behavior is illustrated in Figures 12A to 12C.
Purpose - To install the EVAP. SAVER in a live site and identify the most energy efficient settings for both refrigeration and evaporator power consumption.
Findings We found that when adjusting the unit to 30% the evaporators saved more power but this lead to the refrigeration cycle times increasing hence using more power. We adjusted the unit up to 50% which still had significant savings on the evaporator fans and also reduced the refrigeration cycle times
Data Evidence - This is Illustrated in Figure 11 A to 11C. The results have been taken from fletail care and clearly illustrate the behavior of the unit. In particular, Figure 11 A illustrates the total summary of the Evaporator saver for the past 2 months Figure 11 B identifies the 3 full weeks of data compared to each other. Figure 11C identifies the rotating weeks.
Trial Sites 2&3
Full Supermarket · Compressor rack systems
An installation for cool rooms that are piped from a rack or multiplex system will result in the following;
1. A reduced load on the rack, which will require the installation of compressor cylinder un loaders
(If not already fitted) to fully realize the energy savings to be made.
2. Longer cycle off times tor all compressors. Less wear on compressors and associated parts.
3. 60-75% energy saving on compressor start up due to the presence of un loaders,
4. Reduced energy consumption of evaporators and compressor run times. 5. Adjustment ot cool room evaporator EPR's and calibration ot existing probes will further enhance energy savings whilst keeping the room at a suitable set- point to Coles specifications. Trial Site 2
Site Description Large Supermarket
Plant design - 6 x Medium temperature cool rooms, 5 of which controlled by a
3 compressor multiplex rack system. This rack also controlled other refrigeration equipment within the site so an overall plant saving proposed challenge.
Monitored Power consumption of the entire plant.
Door monitoring on each room.
Power consumption of the evaporators on each room controlled.
Monitoring of humidity In Produce room.
All rack and compressor behavior including temperatures, pressures, cycles etc.
Findings - We found that the EVAP. SA ERS saved power on the
evaporators without any negative impact on product or room temperature.
We cycled the units from 100% to 50% in order to analyse trends. The cool rooms also decreased their refrigeration cycle times hence their runtime which reduced the demand on the rack.
The racks behavior changed and showed a saving reducing compressor cycle time. This was hard to show on the overall rack power consumption but is identified on the history In cycles. we installed capacity control on the 3 compressor rack to try and further achieve savings as the EVAP.SAVERS reduced compressor cycle time and start ups. A refrigeration technician was also introduced to calibrate all cool room evaporators and make sure they were running efficiently with the
EVAP.SAVERS, this was done by making sure the TX Valves on the Coils were adjusted correctty to allow the right amount of refrigeration through the coils. The evidence is shown on Data Evidence - Figures 13 to 14 illustrate the saving of power on the evaporators without any negative impact on product or room temperature.
Trial Site 3
Site Description Large Supermarket
Plant design - 5 x Medium temperature cool rooms 4 of which controlled by a
4 compressor rack system. This rack also controlled other refrigeration equipment within the site so an overall plant saving would be a challenge.
Monitored - Power consumption of the entire plant.
Door monitoring on each room controlled.
Power consumption of the evaporators on each room controlled.
Monitoring of humidity in Produce room.
All rack and compressor behavior including temperatures, pressures, cycles etc.
Findings We found that the EVAP.SAVERS saved power on the
evaporators without any negative impact on product or room temperature.
We cycled the units from 100% to 50% in order to analyse trends. The cool rooms also decreased their refrigeration cycle times hence their runtime which reduced the demand on the rack.
The racks behavior changed and showed a saving reducing compressor cycle time. This was hard to show on the overall rack power consumption but is identified on the history in cycles.
We installed capacity control on the 4 compressor rack to try and further achieve savings as the EVAP.SAVERS reduced compressor cycle time and start ups. A refrigeration technician was also introduced to calibrate all cool room evaporators and make sure they were running efficiently with the
EVAP.SAVERS, this was done by making sure the TX Valves on the Coils were adjusted correctly to allow the right amount of refrigeration through the coils. Data Evidence - the results and savings are very similar to Trial Site 2.
While we have described herein a particular embodiment of an evaporator saver, it is further envisaged that other embodiments of the invention could exhibit any number and combination of any one or more of the features previousfy described. However, it is to be understood that any variations and modifications which can be made without departing from the spirit of the invention are included in the scope thereof.