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Quotes - Engineering - SalesCold loops that sanitize themselves
The heat an ozone loop makes
An ozonated purified water loop carries 0.02 to 0.2 ppm of dissolved ozone from the tank through the piping, and a UV destruct unit at 254 nm strips it out ahead of each use point. Every UV lamp puts most of its input into the water as heat: a 5 kW destruct unit on a 100 gpm loop raises the water about 0.7 C per pass, and with the pump added the loop climbs a degree or two an hour until something removes it.
That something is a loop cooler, and it lives in a harder place than a plain trim cooler because the water on one side of it is an oxidizer.
Heat balance, materials and placement
Adding up the lamps and the pump
The cooler duty is everything that warms the loop. UV lamps convert 85 to 90 percent of their input to heat: a 3 kW TOC unit and two 5 kW destruct units add about 40,000 Btu/h. A 7.5 hp pump adds 19,000 Btu/h. A 3,000 gallon tank and 500 ft of pipe in a 24 C plant pick up another 10,000 to 20,000 Btu/h when the water is held at 20 C, because now the insulation works against you. Call it 75,000 to 85,000 Btu/h with 25 percent margin for lamp aging and summer chilled water: a 1.5 to 2 C rise per pass on a 100 gpm loop, which a small double tubesheet unit removes on 7 C chilled water.
What ozone tolerates and what it eats
Dissolved ozone at loop concentration does nothing to 316L. The damage is to organics: nitrile gaskets crack in weeks, EPDM lasts months and sheds particles as it goes, silicone the same. Every clamp gasket, valve diaphragm and pump seal in the ozonated section is PTFE, PVDF or an ozone-rated fluoroelastomer, and the exchanger ships with those fitted, not the EPDM set that ships by default. The shell side is chilled water and needs nothing special. The one thing ozone asks of the exchanger body is full drainability, because standing ozonated water off-gasses into an ozone-rich pocket that finishes any gasket near it.
Which side of the UV units the cooler goes on
The destruct units sit just ahead of the use points; the cooler goes upstream of them, in the ozonated section, on the return leg or just after the pump. There it removes the heat from every lamp on the loop and it sees ozone, which is why its materials matter. Placed downstream of the last destruct unit it sees clean water but cannot cool the loop between the tank and the use points. The common mistake is exactly that: an engineer specifies EPDM gaskets, the reviewer moves the cooler past the UV to protect them, and the suite complains all summer that the water is 28 C.
The hot sanitization that many ozone loops keep
Ozone sanitizes the wetted surfaces it reaches, but not the tank above the spray pattern, the vent filter, or a dead leg behind a closed valve. Many sites keep an annual hot water sanitization at 80 C for those, and then the loop cooler either survives 80 C on the tube side, which a double tubesheet shell-and-tube does without comment, or is isolated and bypassed. HeatX asks at quote time so the cooler is rated for the hottest thing the loop will ever do.
Send the loop flow, lamp ratings, pump horsepower, tank and pipe details, chilled water temperature and the sanitization method, and the cooler ships with the right gaskets fitted. Call and talk it through with an engineer: 1-805-484-2992
Ozone and UV loop cooler process conditions
Ozone limits what can touch the water, so these rows pair the duty with the materials allowed in the path. Compare them with your loop and send your ozone level and sanitization practice with the quote request.
| Condition | Detail |
| Product | Ozonated USP Purified Water, 0.02 to 0.2 ppm O3 upstream of UV destruct |
| Flow range | 20 to 250 gpm loop flow; the cooler sees the full loop |
| Temperatures in / out | 26 to 30 C in, 20 to 23 C out; continuous |
| Hold | None; ozone contact time is the loop transit, typically 5 to 15 minutes |
| Utility | Chilled water 7 to 10 C or a glycol chiller loop on the shell side |
| Approach | 3 to 5 C; a small unit sized on a modest duty |
| Construction | Double tubesheet straight tube 316L, or double-wall plate for loops that are never steamed |
| Finish / class | 316L, 20 Ra electropolished on the water side; ASME BPE |
| Ozone materials | 316L, PTFE, PVDF and ozone-grade fluoroelastomer in the water path; no nitrile, EPDM, silicone or brass |
| CIP / SIP | Ozone sanitizes continuously; periodic hot water sanitization at 80 C where the SOP keeps it |
Common FAQs
Not at loop concentrations; the passive film is if anything reinforced. The wear is on elastomers and any brass or copper that finds its way into the loop.
It can, and then needs no ozone-rated gaskets, but it cannot cool the water between the tank and the use points. For 20 to 25 C delivery it belongs in the ozonated section.
Roughly 85 to 90 percent of its rated input, so a 5 kW unit adds about 15,000 Btu/h. Add every lamp and the pump to get the cooler duty.
A double-wall plate with PTFE-faced gaskets works on a loop that is never hot-sanitized. If the SOP includes 80 C sanitization, the double tubesheet shell-and-tube is simpler.
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