• AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems
  • AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems

AL-KO HYDRO-OPT® – Efficient Heat and Cooling Recovery in Run‑Around Coil Systems

The AL‑KO HYDRO‑OPT® series of hydraulic stations delivers reliable, energy‑efficient heat transfer within a run‑around coil system. A water‑glycol mixture circulates between the exhaust and supply air coils to transport thermal energy, achieving heat transfer efficiencies of up to 80%. A run‑around heat recovery system offers maximum spatial flexibility, as supply and exhaust air units can be positioned independently throughout the building. This makes it an ideal solution wherever system separation is required due to architectural constraints. In hygiene‑critical environments – such as healthcare facilities, laboratories, and cleanrooms – a run-around coil system is often the only technically and hygienically compliant method for recovering heat or cooling. With AL‑KO HYDRO‑OPT®, all components of the heat recovery system are perfectly coordinated to ensure outstanding energy efficiency, operational reliability, and long‑term economic performance.

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Run-around coil system: Advantages, Function, and Installation – Key Information at a Glance

How does a run‑around heat recovery system work?

When supply and exhaust air must be routed separately within a building, a run‑around coil system provides an ideal solution for heat recovery in central air‑handling systems. The AL‑KO HYDRO‑OPT® hydraulic stations combine high‑performance heat exchangers, advanced control technology, and all required system components into a perfectly matched run‑around heat recovery system with heat transfer efficiencies of up to 80%. This approach ensures strong planning reliability, enables energy‑efficient HVAC system architectures, and supports smooth installation and commissioning by qualified AL‑KO service specialists.

Advantages
  • Makes a significant contribution to energy savings and sustainably reduces operating costs
  • Optimized performance through dynamic, self-regulating volume‑flow control for maximum efficiency
  • High heat transfer efficiency with temperature effectiveness up to µt ≤ 80%
  • Compact design for flexible integration into various air‑handling systems
  • Option to fully decouple the cooling and ventilation system with a single action
  • Preconfigured electrical and hydraulic connections (excluding air‑side sensors)
  • Remote access via AL‑KO REMOTE CONTROL for convenient monitoring and service available
Installation
  • Professional commissioning and support provided by qualified AL‑KO service specialists
  • Fast, secure installation thanks to preconfigured electrical and hydraulic connections
  • Pre‑piped heat exchangers inside the unit reduce installation time and overall project costs

Run-around coil system: Functional Units and Technical Components

We offer a broad range of functions, functional units, and technical components – fully tested and perfectly coordinated to work together. The result is a high‑performance run‑around heat recovery system that ensures maximum energy efficiency, reliability, and planning certainty for central HVAC applications.

Basic Functions
Additional Functions
Heat Exchanger
Control Technology
Optional Components

Hydraulic station AL‑KO HYDRO‑OPT®: Functional Overview and Technical Data

Function Overview – HYDRO-OPT S and HYDRO-OPT M at a Glance
Function Description HYDRO-OPT S HYDRO-OPT M
Number of supply air units 1.9 m3/h 1 1
Number of exhaust air units 4.9 m3/h 1 3
Intelligent pressure-independent control of multiple exhaust air units ✓
Control cabinet with controller and inverter ✓
Control integrated in the inverter ✓
Main switch ✓ ✓
Power control with pump + valve ✓ ✓
Air volume-dependent power control Control via external regulation is possible Used by intelligent DeltaT control implemented
Release signal ✓ ✓
Fault signal ✓ ✓
Control 0–-10 V ✓ ✓
System pressure monitoring warning ✓
System pressure monitoring shutdown ✓ ✓
Frost protection control ✓ ✓
Circulation increase ✓ ✓
Bypass valve ✓ ✓
Bus connection BACnet IP Optional
Bus connection BACnet MSTP Optional Optional
Bus connection Modbus RTU Integrated Integrated
Bus connection Modbus IP Optional
Controllable pump ✓ ✓
Double pump ✓
Pump blockage protection ✓
Pump vent valve ✓ ✓
Display of supply temperature ✓ ✓
Display of return temperature ✓ ✓
Flow meter Mechanical display integrated Electrical display on the display
Manometer ✓ ✓
Expansion vessel and safety valve ✓ ✓
Filling and draining device ✓ ✓
Dirt trap ✓
AL-KO HYDRO-OPT® S
Type Dimension Flow in m3/h Length in mm Width in mm Height in mm Weight in kg
0.5 DN 20 0.35 – 0.55 1178 489 971 105
1.5 DN 25 0.56 – 1.50 1178 489 971 110
3.5 DN 32 1.51 – 3.50 1178 489 971 119
6.5 DN 40 3.51 – 6.50 1178 489 971 133
11 DN 50 6.51 – 11.00 1178 489 971 153

All specifications are approximate values, based on the basic version. Subject to technical changes.

AL-KO HYDRO-OPT® M - 1 Air Supply Unit + 1 Air Exhaust Unit
Type Dimension Flow in m3/h Length in mm Width in mm Height in mm Weight in kg
2 DN 32 0.5 - 1.9 1989 842 1454 approx. 279
5 DN 40 2.0 - 4.9 2142 842 1607 approx. 328
10 DN 50 5.0 - 9.9 2142 995 1760 approx. 390
15 DN 65 10.0 - 14.9 2525 1224 2142 approx. 589
25 DN 80 15.0 - 25.0 2678 1683 2525 approx. 844

All specifications are approximate values, based on the basic version. Subject to technical changes.

AL-KO HYDRO-OPT® M - 1 Air Supply Unit + 2 Air Exhaust Units
Type Dimension Flow in m3/h Length in mm Width in mm Height in mm Weight in kg
2 DN 32 0.5 - 1.9 1760 842 1454 approx. 285
5 DN 40 2.0 - 4.9 1760 842 1607 approx. 338
10 DN 50 5.0 - 9.9 1913 995 1760 approx. 406
15 DN 65 10.0 - 14.9 2219 1224 2142 approx. 618
25 DN 80 15.0 - 25.0 2372 1683 2525 approx. 884

All specifications are approximate values, based on the basic version. Subject to technical changes.

AL-KO HYDRO-OPT® M - 1 Air Supply Unit + 3 Air Exhaust Units
Type Dimension Flow in m3/h Length in mm Width in mm Height in mm Weight in kg
2 DN 32 0.5 - 1.9 1989 842 1454 approx. 285
5 DN 40 2.0 - 4.9 2142 842 1607 approx. 363
10 DN 50 5.0 - 9.9 2142 995 1760 approx. 434
15 DN 65 10.0 - 14.9 2525 1224 2142 approx. 663
25 DN 80 15.0 - 25.0 2678 1683 2525 approx. 939

All specifications are approximate values, based on the basic version. Subject to technical changes.

Contact

Need more information about AL‑KO’s run‑around coil system solutions? Our specialists are available to support you directly – quickly, expertly, and with a clear focus.

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Downloads – Hydraulic station AL-KO HYDRO-OPT®

Your strong Partner for Run‑around Coil Systems and efficient Heat Recovery

AL‑KO Airtech is a leading manufacturer of innovative ventilation systems and air‑handling technology. More than five decades of engineering expertise flow into the development of modern run‑around coil systems and high‑performance components such as the AL‑KO HYDRO‑OPT® hydraulic stations. We rely exclusively on high‑quality, independently tested components whose performance has been verified by accredited testing institutes. All installed heat exchangers are Eurovent‑certified and undergo regular third‑party performance validation. Commissioning and service are carried out by qualified AL‑KO specialists.

 

Your additional Benefits:

  • Over 50 years of experience in ventilation and HVAC technology
  • Complete run‑around heat recovery systems from a single source – perfectly matched and integrated
  • In‑house engineering and manufacturing for maximum quality
  • Eurovent‑certified high‑performance heat exchangers
  • Proven solutions for hygiene‑critical applications
  • Professional commissioning and expert support from AL‑KO service personnel

Frequently Asked Questions (FAQ) about Run‑Around Coil Systems

1. What is a run‑around coil system?
A run‑around coil system is an efficient technology for heat and cooling recovery in air‑handling systems, especially when supply and exhaust air must be routed separately within a building. It consists of at least one coil in the supply air stream and one in the exhaust air stream, connected through a shared hydraulic circuit. A water‑glycol solution circulates between the coils and transports the thermal energy.

 

2. How does a run‑around heat recovery system work?
The exhaust‑air coil extracts energy from the used indoor air and transfers it to the circulating glycol solution. This is then pumped to the supply‑air coil, where it delivers the stored energy to the incoming fresh air and preheats it. During summer operation, the process works in reverse: the exhaust air transfers cooling energy to the glycol solution, which is then used to cool the supply air.

 

3. What advantages does a run‑around coil system offer compared to other heat recovery technologies?
A key advantage over rotary and plate heat exchangers is the complete separation of the airstreams. This prevents any transfer of particles, contaminants, odors, viruses, or bacteria – making the system ideal for hygiene‑critical environments. A run‑around heat recovery system also offers exceptional flexibility in building design, as the hydraulic circuit can bridge long distances and different floors. The AL‑KO HYDRO‑OPT® M even supports connecting up to three exhaust‑air units to one system, providing significant economic benefits.

 

4. Where are run‑around heat recovery systems typically used?
They are used in applications with strict requirements for hygiene, efficiency, or building layout. Typical areas include healthcare facilities such as hospitals and clinics, laboratories, cleanrooms, and pharmaceutical production sites, as well as industrial halls with corrosive or contaminated exhaust air. Run‑around coil systems are also widely used in office and administrative buildings where supply and exhaust air systems are installed on different floors or in separate technical rooms.

 

5. Why are run‑around coil systems especially suitable for hygiene‑critical environments?
The supply and exhaust air streams are completely separated by design, no air‑side transfer can occur – even in the unlikely event of a leak or system failure. This ensures that contaminants, odors, particles, or microorganisms cannot be transferred between airstreams. This separation makes the run‑around coil system the preferred solution wherever hygiene and clean‑air quality are top priorities.