A run-around coil heat recovery system uses two finned coils connected by a closed glycol loop. A pump circulates the fluid between the exhaust coil, where it picks up heat, and the supply coil, where it releases heat into the incoming air.
When to Use a Run-around Coil
This design is ideal when the supply and exhaust ducts are far apart or on different floors. Because the coils are separate and connected only by piping, installation flexibility is much higher than with plate or wheel exchangers.
System Components
- Exhaust air coil (finned tube)
- Supply air coil (finned tube)
- Circulation pump
- Expansion tank and glycol-water mixture
- Controls and temperature sensors
Pros and Cons
Pros:
- No risk of cross-contamination
- Works over long distances
- Easy to retrofit into existing ductwork
- Can recover heat from multiple exhaust points
Cons:
- Lower efficiency than counter-flow plate or rotary wheels (typically 40–60 %)
- Requires pump power and maintenance
- Glycol solution must be checked periodically
Common Applications
- Kitchen and laboratory exhaust
- Multi-zone commercial buildings
- Industrial processes with remote exhaust stacks
- Swimming pools and locker rooms
Controls and commissioning determine whether a run-around coil reaches its rated recovery. A variable-speed glycol pump trimmed to outdoor and exhaust temperatures lets the loop deliver more heat in winter and coast in mild weather, while a motorized bypass keeps supply temperature within setpoint. Integrate the pump and dampers with the building management system using dry contacts or a network link so the recovery runs only when the exhaust fan is on. During commissioning, balance flow to the design rate, confirm there are no air locks in the high points, and verify the expansion tank charge. Our heat recovery solutions include factory-tested coil bundles and control packages for retrofit projects.
よくある質問
What glycol concentration is typical?
A 30–50 % propylene glycol solution is common, depending on freeze protection requirements.
Can run-around coils recover humidity?
No. They are sensible-only systems and do not transfer moisture.
よくある質問
Pros:nnNo risk of cross-contaminationnWorks over long distancesnEasy to retrofit into existing ductworknCan recover heat from multiple exhaust pointsnnCons:nnLower efficiency than counter-flow plate or rotary wheels (typically 40–60 %)nRequires pump power and maintenancenGlycol solution must be checked periodicallynnnCommon ApplicationsnnKitchen and laboratory exhaustnMulti-zone commercial buildingsnIndustrial processes with remote exhaust stacksnSwimming pools and locker roomsnnnControls and commissioning determine whether a run-around coil reaches its rated recovery. A variable-speed glycol pump trimmed to outdoor and exhaust temperatures lets the loop deliver more heat in winter and coast in mild weather, while a motorized bypass keeps supply temperature within setpoint. Integrate the pump and dampers with the building management system using dry contacts or a network link so the recovery runs only when the exhaust fan is on. During commissioning, balance flow to the design rate, confirm there are no air locks in the high points, and verify the expansion tank charge. Our heat recovery solutions include factory-tested coil bundles and control packages for retrofit projects.nFrequently Asked QuestionsnWhat glycol concentration is typical?
A 30–50 % propylene glycol solution is common, depending on freeze protection requirements.
Can run-around coils recover humidity?
No. They are sensible-only systems and do not transfer moisture.
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当社のエンジニアが風量、温度、圧力損失の予算に合わせてコアを設計し、用途に応じて板式・回転式・ヒートパイプ回収を選定します。以下をお読みください： 熱交換器ガイド 、または仕様についてお問い合わせください。
関連製品
HVAC および換気向けの板式・回転式・ヒートパイプ回収。
空気と液体用の大表面積固定コア。
大風量向け高効率エネルギー回収。
清浄用途向けの受動的・完全分離流。