| - SRV do not use the four-way valve in the outdoor unit. That means there is no reverse in flow. Instead of using the four-way valve in the outdoor unit, SRV uses solenoid valves and check valves to insure the proper functioning of the system with a one-way flow in both heating and cooling mode. - The distance between indoor and outdoor units can reach more than 100 meters. All indoor units will be installed on the interior walls. These SRV features allow the installation of the air conditioning system, in tall buildings, in one specific place without distorting the building’s facade. - SRV has no control cable between indoor units and outdoor units. In order to make all the system in harmony, each outdoor compressor has its own settings. The Low pressure controls the cooling mode, and the high pressure controls the heat mode, with the assistance of some sensors to control the outdoor fan speed (3 speeds) and for safety reasons. - SRV has no reversing valve; the low pressure pipe never faces high pressures and heat. It is replaced by plastic tubing as PPR, CPVC, PEX, or even agriculture pipes. - Units can be added to the SRV system any time during his function, without the need to turn off the system. - In cooling mode, each indoor unit can be in heat or cool mode, up to 40% of the capacity of the outdoor unit. - The outdoor fan can be rotated in four directions and can discharge the hot air vertically. - The electrical consumption is up to 35% lower than other air conditioning systems. SRV does not use Direct Current nor inverter, SRV use normal compressors. This SRV feature reduces the electronic components to the max, in other words no converters mean less loss in power. - Unlike standard air conditioning models, SRV has a unique decorative shape. - SRV outdoor units can be installed side by side without losing spaces between the units. This SRV feature allows a higher number of Units to be installed in the same space. |
Outdoor unit shape:
The unit has a square base (1). Closed from the sides and has an access door in the front. The coil is rectangular and covers the back side. The fan is at 45 degrees and covered by a box with a gril l allowing the air to go sideways (3) or up (4) way as needed. And the box works as a sound absorber. Two units can be embed together to give bigger capacity (2). All units with capacity of 12, 14, 18, 20, 24, 30 thousand BTUs have the same size. This feature allows reducing occupied space upon installation.
The upper part that holds the fan can be rotated, allowing the air to go from all sides.
This flexibility in installation is a key feature in SRV.
Outdoor units connection:
Cupper can be mounted from three sides (5). It is connected directly to a refnet: one end goes to the first unit inlet valve, the second to an inlet valve for preparation to install a second unit (6).
When adding a second unit, a refnet is mounted for future installation of a third unit, ending with an inlet valve. One end of the second refnet goes to the inlet valve in the second unit.
Basic system:
Direction of solenoid and check valves to be strictly followed:
Outdoor unit: (for units 12-14-18-20-24-30 thousand BTU Freon 22 and 410)
Sizes of solenoids:
Solenoid valves:
SV 1-2: 3/8 inch
SV 3-4: 5/8 inch
SV 11: 1/4 inch
Check valves:
CK 6-7-9: 3/8 inch
CK 5-8-10: 5/8 inch
Inlet valves:
IV 12: 3/8 inch
IV 13: 5/8 inch
Accumulator Volume: (depending on unit size)
AV 14: 1 to 1.5 liters
AV 15: from 6 to 8 liters
Fan: 450-850 cfm (depending on unit size)
Coil: depending on the size of compressor. To be selected upon manufacturing (standard procedure)
Oil separator, sight glass, filter drier 3/8 inch, to be installed for each unit separately.
Kit Unit: to be with the indoor unit. It is installed from 1.5m to 5m away from indoor unit.
1 | P a g e
SUBSTITUTE SHEETS (RULE 26) Solenoid 'wo 2023/080803 way valve 3/8- 5/8 PCT/QA2022/050002
Expansion valve: can be fixed capacity as restrictor or capillary. Or modulating as electronic expansion valve or with bulb.
A charging valve is for vacuum and Freon charge.
Fan has a standard coil and fan, PCB Board.
Cooling mode:
Outdoor unit:
Super-heated gas will pass in the oil separator leaving all traces of oil to return to the suction. Check valve 9 will make sure that no return gas will go to the compressor when turned off. Solenoid valve (2) is open giving the superheated gas to the coil. The fan cools the coil. Pressure is high, gas will not pass in check valve 5, but in CK 6 it will pass. CK 7 will make sure that no gas will return to the outdoor unit when it's turned off. The accumulator will receive the liquid with high pressure. All over needed liquid will hold in the accumulator. When an indoor unit is turned on, the liquid will exit the unit through the inlet valve.
When returning through the gas inlet valve, as gas, it will come into an accumulator to transform any liquids into gas. Solenoid valve 4 is open to arrive to check valve 10. Finally returning to the compressor and the cycle is closed. Solenoids 1 and 3 are closed in cooling mode.
Indoor unit:
When the solenoid valve in the kit opens, hot liquid goes into the four way valve to the expansion. The act of cooling happens and the fan does the heat exchange with the space. Then returning to the four way valve, through the refnet to the outdoor unit. And it's a closed system.
Heat mode:
Outdoor unit:
Super-heated gas will pass in the oil separator leaving all traces of oil to return to the suction. Check valve 9 will make sure that no return gas will go to the compressor when turned off. Solenoid valve 1 is open giving the superheated gas to the accumulator. CK 7 will make sure that no gas will return to the outdoor unit when it's turned off. Then to liquid inlet valve to the fan. When returning through the gas inlet valve, as gas, it will come into an accumulator to transform any liquids into gas. CK 8 will prevent gas from returning to pipes, through CK 5 to the coil, the freezing gas will lose its heat to the fan. Returning through CK 10 to the compressor. And it's a closed circuit. Solenoids 2 and 4 are closed in heat mode.
Indoor unit:
When the solenoid valve in the kit opens, superheated gas goes into the four way valve to the fan coil. The fan does the heat exchange with the space. Then returning to the expansion valve. The act of cooling happens and it returns to the outdoor unit through the refnet. And it's a closed system.
2 | P a g e
SUBSTITUTE SHEETS (RULE 26) N.B: In SRwo 2023/080803 id line and suction line do not switch. That will mapcT/QA2022/050002 modes, cooling and heating, always at low pressure. Resulting the possibility to install plastic tubing. For example PPR, or CPVC, or others.
With Freon 22, max pressure will not exceed 75 PSI. With Freon 410a, max pressure will not exceed 140 PSI. Knowing that PPR can hold 300 PSI at 60 degrees Celsius. Temperature in SRV will be less than 5 degrees.
In cooling mode only:
Liquid line will have hot liquid Freon. Not super-heated, but contains enough heat to work in an average heat season, like autumn or spring. For example, men who wear suits will need cooling. But women will request heating (usually). And it depends on the exposure of the space to the sun, some will be hotter than others.
In such case, SRV gives the solution and everyone is happy.
But, the suction line will be freezing. To regulate this issue, the outdoor fan will stop from working depending on the system's needs. That will regulate the pressure in the liquid line so that both heat and cool are working together normally. This is a key feature in SRV.
Controls:
Indoor unit:
In cooling mode, solenoid is turned on to let liquid go into the fan coil. The expansion, if it's electronic (EEV), will give the needed amount of refrigerant.
In heat mode, the four way valve is powered to reverse the cycle. Super-heated gas will go into the fan coil. The EEV will do the same work as cooling.
Sensors can be added for more data and controls and safety.
Outdoor unit:
A PCB Board controls the outdoor unit. It is connected to a power source with a breaker. All SV, sensors and pressure switches are also connected. In cooling mode SV 2 and SV 4 are opened when the compressor is on. In heat mode SV 1 and SV 3 are open.
When the unit is powered, the compressor starts working.
In cooling mode, the pressure in suction will drop from the normal state to reach the pressure of 35 PSI in r22 and 60 PSI in r410a. The PCB turns off the compressor.
In heat mode, the pressure in liquid line will reach up to 325 PSI in r22, and 410 psi in r410a. The PCB will turn off the compressor.
When any indoor unit is switched on,
3 | P a g e
SUBSTITUTE SHEETS (RULE 26) In coolingwo 2023/080803/ pressure will rise from 35 PSI. When pressure reapcT/QA2022/050002CB turns on the compressor. And relatively in r41Oa, when it reaches 110 PSI, the PCB will turn on the compressor.
In heat mode, the high pressure will drop from 325 PSI to 225 PSI, then PCB will turn on the compressor. Relatively in r410, when it drops from 410 PSI to 275 PSI, the PCB will turn on the compressor.
When multiple outdoors are joined together, the set point of the on and off of the compressors will have a differential. For example:
Three outdoor units as follows:
R22:
R410a:
Unit size (cm):
The unit size should be as compact as possible.
4 | P a g e
SUBSTITUTE SHEETS (RULE 26)