Heat Recovery VRF System

All indoor units are cooling. The system works like a standard VRF, rejecting all heat outdoors. This is common in Indian summers.

Most zones are cooling, while a few are heating. Recovered heat serves the heating zones, and the outdoor unit rejects the remaining heat.

Cooling and heating demands are roughly equal. Heat is transferred between zones with minimal outdoor unit work. This is the most efficient operating mode.

Most zones are heating, while a few are cooling. Heat from the cooling zones supplements heating, and the outdoor unit absorbs the balance from outdoor air.

All indoor units are heating, and the outdoor unit absorbs heat from outdoor air, just like a heat pump VRF in winter.

Heat recovery outdoor units are modular and can be combined for higher capacities in commercial projects.

Inverter compressors deliver precise capacity control and high part-load efficiency.

These are the heart of the heat recovery system. They contain valves that route refrigerant to each zone in cooling or heating mode.

Depending on the brand, a three pipe VRF system uses a liquid line, a suction gas line, and a discharge gas line. A two pipe heat recovery VRF uses a special BC controller to separate refrigerant phases.

VRF refnet joints, Y joints, and headers split the VRF heat recovery piping evenly to branch selectors and indoor units.

EEVs in each indoor unit fine-tune refrigerant flow for precise zone temperature control.

Cassette, ducted, hi wall, floor standing, and fresh air units connect to the system to suit different room types.

Room controllers, central controllers, and BMS gateways provide full control and monitoring.

The 3 pipe heat recovery VRF design uses three refrigerant lines from the outdoor unit to the branch selector boxes. It is widely used and offers straightforward refrigerant distribution.

A 2 pipe heat recovery VRF uses a BC controller that separates liquid and gas refrigerant, allowing simultaneous heating and cooling with only two pipes from the outdoor unit. A heat recovery VRF with BC controller reduces piping and brazing work.

When comparing two pipe vs three pipe heat recovery VRF, both deliver simultaneous heating and cooling. The right choice depends on the brand, building layout, and piping complexity.

Single-port BS boxes serve one indoor unit or group and suit spread-out layouts. Multi-port BS boxes serve several zones from one box and reduce the number of units to install and maintain.

Water-cooled heat recovery VRF uses a water loop instead of outdoor air for heat exchange. It is useful in high-rise buildings and where outdoor space is limited.

Hydro units connected to the heat recovery system use recovered heat to produce hot water for bathrooms, kitchens, or underfloor heating, adding another layer of energy savings.

VRF wall mounted indoor units suit bedrooms, cabins, and small offices.

VRF cassette indoor units fit in false ceilings and suit open offices, lobbies, and showrooms.

VRF ducted indoor units and VRF ceiling concealed units are fully hidden, with only grilles and diffusers visible.

These suit perimeter zones, glazed walls, and rooms without false ceilings.

Dedicated units treat outdoor air before supplying it to the building, improving indoor air quality.

We calculate both cooling and heating loads for every zone. This VRF load calculation is the foundation of heat recovery VRF system design.

We study when cooling and heating demands overlap across the day and year to confirm whether heat recovery will deliver real savings.

Outdoor capacity is selected based on peak combined loads, applying a suitable VRF diversity factor and staying within the allowed VRF combination ratio.

Indoor units that always operate in the same mode can share a BS port, while zones needing independent heating and cooling get dedicated ports.

VRF refrigerant piping is sized and routed within the manufacturer's limits for total length, farthest unit, and height difference.

Room volumes are checked against the refrigerant charge to ensure safety in case of leaks, with additional measures added where needed.

By reusing heat from cooling zones to warm heating zones, an energy efficient heat recovery VRF system avoids producing that heat separately, which delivers significant savings in buildings with simultaneous loads.

Inverter compressors match output to demand, avoiding the energy waste of on/off cycling.

Buildings operate at part load most of the time, and heat recovery VRF systems are highly efficient in these conditions.

Most heat recovery VRF systems use R410A. R32 heat recovery VRF systems are also available, offering lower global warming potential. Compress India can advise on the best option for your project.

Each room controller lets occupants choose cooling or heating, set temperature, and adjust fan speed.

Central controllers allow facility teams to monitor all zones, set schedules, and limit setpoints.

Heat recovery VRF BMS integration through VRF BACnet or VRF Modbus gateways connects the system to the building management system.

Remote monitoring platforms provide alerts, performance tracking, and control from anywhere.

In multi-tenant buildings, energy use is apportioned to each tenant for accurate billing.

These units condition 100% outdoor air before supplying it to the rooms, maintaining air quality and humidity control.

A heat recovery ventilator (HRV) or energy recovery ventilator (ERV) exchanges energy between outgoing exhaust air and incoming fresh air. An HRV system recovers heat only, while an ERV system also transfers moisture. Pairing a heat recovery VRF with a commercial energy recovery ventilator adds a second layer of energy savings on the fresh air side.

A DOAS handles all fresh air separately, allowing the VRF system to focus on room loads.

Different zones can be cooled and heated at the same time, delivering true independent heating and cooling zones.

Recovered heat reduces the energy needed for heating, lowering overall running costs.

Every occupant controls their own mode and temperature.

One system replaces separate cooling and heating plants, saving space and simplifying operation.

Heat recovery VRF adapts to changing loads through the day and across seasons.

Hydro units can use recovered heat to produce hot water, adding further savings.

Branch selectors, additional piping, and more advanced outdoor units increase the upfront cost.

3-pipe systems and BS boxes need careful design and installation.

BS boxes need ceiling space and service access, and they should be located away from noise-sensitive rooms because of refrigerant noise during mode changes.

Leak prevention, detection, and refrigerant concentration checks are essential.

If a building needs only cooling most of the year, the extra cost of heat recovery may not be justified.

Brazing, pressure testing, vacuuming, and charging must be done precisely by trained technicians.

Compress India carries out simultaneous load analysis before recommending heat recovery VRF, so you invest only where it delivers real value.

A heat recovery VRF for hotels lets guests choose heating or cooling individually, and hydro units can use recovered heat for hot water.

A heat recovery VRF for hospitals provides precise, individual comfort for patient rooms, consultation areas, and offices with different needs.

In a heat recovery VRF for office buildings, core zones often need cooling while perimeter zones need heating in winter, which makes heat recovery ideal.

Heat recovery VRF lets each room choose heating or cooling, with optional hot water generation.

Heat from server rooms that need year-round cooling can be reused to warm office areas.

Classrooms, labs, and hostels benefit from zone-wise heating and cooling.

A heat recovery VRF for mixed-use buildings handles retail, office, and residential zones with different loads and schedules.

In colder and mixed-climate regions, heat recovery VRF delivers efficient heating in winter and cooling in summer. It is also well suited to heat recovery VRF for high rise buildings in these regions.

Daikin heat recovery VRF, sold as VRV Heat Recovery, is a widely used 3-pipe heat recovery system with branch selector boxes.

The Mitsubishi VRF heat recovery system, City Multi R2, uses a 2-pipe design with a BC controller for simultaneous heating and cooling.

Hitachi offers heat recovery VRF systems with modular outdoor units for commercial buildings.

Toshiba offers heat recovery VRF systems designed for efficient simultaneous heating and cooling.

LG Multi V Heat Recovery systems provide simultaneous heating and cooling for commercial and residential projects.

Samsung DVM Heat Recovery systems offer modular outdoor units and flexible zoning.

Carrier offers heat recovery VRF systems for commercial applications.

Filters are cleaned regularly and coils are cleaned periodically to maintain airflow and performance.

Outdoor coils are cleaned to maintain heat exchange efficiency.

BS box valves, wiring, and insulation are checked for correct operation and leaks.

Joints, valves, and BS box connections are inspected for leaks.

Error codes are analysed to identify and fix faults quickly.

• Comprehensive AMC: Covers scheduled maintenance plus specified spare parts, with predictable annual costs.
• Non-Comprehensive AMC: Covers scheduled maintenance and service visits, with spare parts charged separately.

Causes: BS box valve faults, controller settings, or wiring issues.

Solution: Check BS box valves, controller configuration, and wiring.

Causes: failed solenoid or expansion valves, or electrical faults.

Solution: Diagnose using error codes and replace faulty valves or boards.

Causes: BS box located near occupied rooms, or missing acoustic treatment.

Solution: Relocate the BS box where possible or add acoustic insulation.

Causes: poor brazing, vibration, or damaged pipes.

Solution: Locate and repair leaks, pressure test, vacuum, and recharge.

Causes: loose wiring, addressing errors, or sensor and PCB faults.

Solution: Check wiring, re-address units, and replace faulty components.

Causes: incorrect piping design, long vertical rises, or low refrigerant charge.

Solution: Review piping and charge, and follow manufacturer oil return guidelines.

Older chiller and boiler systems can be replaced with heat recovery VRF, freeing plant room space and reducing energy use.

Ageing VRF systems can be upgraded to modern heat recovery systems with higher efficiency and better controls.

Indoor units or hydro units can be added within the system's capacity and piping limits.

Upgraded controllers and BMS gateways improve monitoring and energy management.

Heat recovery VRF is priced per HP of outdoor capacity and typically costs more per HP than heat pump VRF because of its more advanced outdoor units and controls.

BS boxes or BC controllers add to the system cost. Multi-port boxes can reduce cost per zone. Indoor unit cost depends on type and capacity.

3-pipe refrigerant piping, insulation, brazing, BS box installation, ductwork, controllers, and BMS integration form a significant part of the total cost.

Building size, number of independent zones, indoor unit types, piping lengths, hydro units, fresh air systems, and controls all affect the final price.

Share your floor plans with Compress India to receive an accurate heat recovery VRF quotation.