I have a client who currently chills their thermoplastic injection mould machines via a chilled water system that consists of an indirect loop system. This has two water tanks. The first (the hot tank) receives the heated water back from the mould heads and is piped via a balance pipe to the cold tank. The cold tank water is pumped to the mould heads. These tanks have their own pump set operating in a loop.

The chillers are piped into the tanks with the flow being to the cold tank and the return from the hot tanks. This circuit also has its' own loop pump set. These tanks are open vented with a top up tank above.

The client would like to have a closed loop system. I have suggested that this can be done using a chilled loop system complete with its' own pump set and a buffer vessel. The mould head loop would be connected directly into the chiller loop with its' own pump set. I thought this would be OK, but now I am concerned that the water return temperature from the mould heads may be too high for satisfactory control.

Any one have any experience of injection moulding close loop or is this a no no without a intermediate heat exchanger?