Knowledge base
Wherever heat has to leave a building or a plant without using water, the usual arrangement is a plate heat exchanger inside and an air-cooled radiator or dry cooler outside, joined by a closed glycol circuit. The plate exchanger separates the inside circuit from the outdoor one; the radiator releases the heat to the air. This guide explains why the pair works so well and what each part is there for.
The Arrangement
The process, engine or building circuit passes its heat to the plate exchanger. On the other side of the exchanger a glycol circuit carries that heat outdoors to the radiator, where fans blow air through finned coils and the heat leaves. The glycol returns cooled to the plate exchanger. The two circuits are separate: what is inside never meets the outdoor glycol, and the outdoor circuit never meets the inside water.
Why Keep The Glycol Outside
Glycol protects the outdoor circuit from frost, which a plain water circuit in an exposed radiator could not survive. But glycol is a poorer carrier of heat than water and is costly to fill over a long pipe network, and many inside circuits do not want it. The plate exchanger lets glycol stay in the outdoor loop only, while the building or process circuit stays on plain water.
Free Cooling And Heat Rejection In Data Centers
In a data center the same pair provides free cooling: when the outdoor air is cool enough, the radiator and plate exchanger take over from the chillers and the compressors rest. The plate exchanger's ability to bring the two circuits close in temperature is what makes this worthwhile. The same arrangement serves engine plants, where it releases the heat of the engine circuit to the air without water.
What The Pair Needs To Work Well
The exchanger and the radiator have to be designed together: the radiator must be able to cool the glycol to the temperature the exchanger needs, and the exchanger must give the inside circuit the temperature it asks for. Pumps, expansion, filling and air removal have to be right, and the glycol mixture kept in order. TECS Engineering designs and delivers plate heat exchanger solutions for engine, power plant and industrial cooling circuits, and builds the air-cooled radiators and dry coolers that go with them; send the duty and the site conditions and the engineering team will answer.
In Short
- Plate exchanger inside, radiator or dry cooler outside, glycol between them
- The inside circuit and the outdoor circuit never mix
- Glycol only where frost protection is needed, plain water inside
- Free cooling in data centers when the outdoor air allows
- Exchanger and radiator designed as a pair
- Pumps, expansion and glycol quality keep the loop healthy
What To Send With An Enquiry
- The inside circuit: fluid, heat duty, temperatures
- Required temperature of the cooled fluid
- Site ambient temperature, altitude and air quality
- Frost protection needed and the glycol mixture
- Space for the radiator outdoors and for the exchanger inside
- Sound limit and the power supply for the fans
Questions We Are Often Asked
Why use a plate exchanger between the building and the radiator?
To keep the outdoor glycol loop separate from the inside circuit, so the inside can stay on plain water and a leak on one side does not reach the other.
Is glycol always needed in the outdoor circuit?
Wherever frost is possible. In frost-free climates a plain water circuit can be enough.
What is free cooling?
Using cool outdoor air to cool the circuit instead of running chillers, through a radiator and a plate exchanger.
Do the exchanger and the radiator have to be designed together?
Yes, because the radiator's outlet temperature is the exchanger's inlet temperature and each limits the other.
What if the outdoor air is too warm?
Then the radiator cannot cool enough alone and a chiller or another source tops up, or the design is made for the hottest day.
Contact Us
Send us the heat duty, the fluid temperatures and flow rates, the ambient conditions and the installation limits. We answer with a design proposal - or write to us on WhatsApp.
