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Cofreth
19-12-2014, 05:33 AM
I want to built-up a chilled water cooling system with a single phase inverter condensing unit. The temperature of the cooling water will be maintaining at around 8 degrees C. But how am I going to produce a signal to the condensing unit to call for the inverter condensing unit to start and also to control the temperature of the chilled water. Is it possible to start an inverter condensing unit without using the indoor pcb circuit and controls, how am I able to control the temperature, please advice, thank you for your feedback.

Glenn Moore
19-12-2014, 11:20 PM
Hi Cofreth
The signal to start the invertor and control the speed of the compressor depends on the Invertor type. Most Invertors use either a 0-10volt signal or a 0/4-20ma signal. So you require a sensor that can give you one of these signals from a sensor measuring the chilled water flow or return temperature. You then set in the invertor the temperature you require the invertor to control at, and then calibrate the input signal accordingly. Most Invertor manufacturers also supply various control devices to match their invertor, but I know that Danfoss in their industrial sensors can supply suitable temperature sensors with 4-20ma out put.
Once you have calibrated the sensor to the invertor you simply give the invertor a GO signal interlocked with a flow switch, and the invertor will speed up and down with the signal coming from the sensor. The invertor will have many options of how it operates but you need to discus this with the invertor supplier who should be able to help you set the Invertor parameters to satisfy the application Good Luck your going the right way

monkey spanners
20-12-2014, 04:40 PM
Are you planning to modify a air con system, or is this a proper refrigeration condensing unit?

If its air con, you are going to have to fool it into thinking it is still cooling air and connected to its proper indoor unit.

install monkey
20-12-2014, 09:29 PM
best option is use a fridge condensing unit 3phase compressor and fitting an abb ach550 inverter drive or other similar then you can customise the ramp up time- either based on just time or as glen mentions using a transducer giving a variable output- using an inverter ac condenser wont work as you would need an indoor pcb to communicate with the outdoor and the sensors for coil temp,return air woudnt work in your application

Cofreth
22-12-2014, 08:18 AM
Are you planning to modify a air con system, or is this a proper refrigeration condensing unit?

If its air con, you are going to have to fool it into thinking it is still cooling air and connected to its proper indoor unit.

Hi monkey spanners,

Yes, I plan to use a normal air-con inverter condensing unit as the present market here, nobody is selling non inverter air-conditioner anymore.

So in your opinion, I have to use back all indoor pcb, sensors , indoor fan motor and swing motor etc to fool the system to start-up, how about the control of water temperature, as the wireless remote controller can only set to lowest 15 degrees C.

I wonder a 5-10V or 4-20ma can startup the air-con inverter condensing unit thru the signal input n the condensing unit, thanks.