Large commercial buildings rarely operate with uniform heating or cooling needs. South-facing rooms may need cooling while shaded or internal areas demand heating. The Mitsubishi Electric City Multi R2 Series provides an intelligent solution. As the world’s first two-pipe heat recovery VRF system, it allows simultaneous heating and cooling while reducing installation complexity and running costs.
This article covers the full R2 range, technical specifications, installation considerations, compatible indoor units, and real project examples across the South of England.
Explore our commercial installation services:
https://www.climateworks.co.uk/commercial-air-conditioning
Why Choose the R2 Series
The R2 Series is designed for environments where heating and cooling requirements coexist. By transferring waste heat from one zone to another, the system reduces energy use and improves comfort. The two-pipe design simplifies installation compared with traditional three-pipe systems, cutting both material and labour requirements.
This makes it well-suited to:
- Multi-tenant office buildings
- Hotels with bedrooms, restaurants, and event spaces
- Universities and schools with classrooms and labs
- Retail complexes operating long hours
- Healthcare facilities with sensitive spaces
R2 Outdoor Unit Range
The R2 range is built for scalability, from single modules to large multi-unit systems.
Representative models include:
- PUHY-HP250YJM-A – 25 kW (8 HP)
- PUHY-HP300YJM-A – 30 kW (10 HP)
- PUHY-HP400YJM-A – 40 kW (14 HP)
- PUHY-HP500YJM-A – 50 kW (18 HP)
- PUHY-HP600YJM-A – 60 kW (22 HP)
Multiple outdoor units can be combined to deliver systems of up to 150 HP, giving designers the flexibility to meet large-scale requirements without moving away from the VRF format.
Compatible Indoor Units
The R2 connects with Mitsubishi Electric’s complete portfolio of City Multi indoor units.
- 4-way ceiling cassettes – 360° airflow for open-plan layouts
- Compact cassettes – ideal for low ceiling depths
- Slim ducted units – designed for refurbishments with minimal void space
- Medium and high static ducted units – supporting long duct runs
- Ceiling-suspended units – simple solution when no false ceiling is available
- Wall-mounted units – compact zoning for smaller spaces
- Floor-standing concealed units – perimeter comfort applications
- AHU interface units – linking air handling systems with VRF
This flexibility ensures the R2 Series can be applied in almost any architectural or functional context.
Technical Specifications
- Refrigerant: R410A
- Capacity range: 22–150 HP modular
- Pipe length: Up to 1,000 m total, 165 m to the furthest indoor unit
- Vertical separation: Up to 90 m
- Indoor units: Over 50 per system (depending on capacity)
- Operating conditions: Cooling –5 °C to 46 °C; Heating –20 °C to 15 °C
These specifications make the R2 suitable for tall buildings, large footprints, and mixed-use facilities.
Installation Considerations
Outdoor Units
- Position in open, ventilated areas to prevent short cycling
- Allow clearances for maintenance and service access
- Select anti-corrosion finishes where environmental exposure is a concern
Refrigerant Pipework
- Install approved BC (Branch Controller) units to manage the two-pipe recovery system
- Observe recommended pipe diameters and lengths for reliability
- Provide oil traps in vertical risers where required
Electrical and Controls
- Supply dedicated circuits for each outdoor module
- Ensure compliance with BS 7671 wiring standards
- Connect all units through the M-NET control network
Controls and Monitoring
The R2 system supports a full suite of control options:
- PAR-40 wired controllers for local zone control
- Centralised controllers for whole-building scheduling
- Energy monitoring interfaces to track system usage
- BMS integration via BACnet, Modbus, or LonWorks
- Cloud-based monitoring for facilities teams managing multiple sites
These options help building operators optimise energy use and maintain comfort across varied occupancy profiles.
Local Project Examples
Winchester University Campus
An R2 system was installed across multiple teaching blocks to balance heating in shaded lecture theatres with cooling in sun-exposed classrooms.
Basingstoke Office Redevelopment
PUHY-HP400 modules provided heating and cooling across 10 floors, with ducted units in open-plan offices and cassettes in meeting rooms.
Reading Hotel
A 90-room hotel combined PUHY-HP300 and HP500 units, with BC controllers transferring waste heat from kitchens to bedroom wings.
Surrey Healthcare Facility
A medical centre integrated R2 units with AHUs to provide both fresh air and controlled comfort conditions.
Benefits of the R2 Series
- Simultaneous heating and cooling for diverse zones
- Two-pipe design reduces complexity and cost
- Heat recovery improves sustainability and lowers bills
- Flexible indoor unit choice to suit every space
- Scalable capacity for medium to very large projects
- Advanced controls for integration with modern building management systems
Q&A
Q: How does the R2 system achieve heat recovery with only two pipes?
The system uses BC controllers to direct refrigerant, allowing heating and cooling simultaneously without a third pipe.
Q: How many indoor units can connect to one R2 system?
Depending on configuration, more than 50 indoor units can be supported.
Q: What is the maximum vertical separation between outdoor and indoor units?
Up to 90 m, making it suitable for tall buildings.
Q: Can the R2 connect to existing ventilation systems?
Yes, through AHU interface units it can link to mechanical ventilation.
Q: Is it suitable for phased construction?
Yes, modular design allows new outdoor units to be added as the project expands.
Installation Tips
- Conduct full heat load analysis before selection
- Position BC controllers for accessibility and optimal pipe routing
- Plan ceiling coordination early to avoid clashes with ductwork and lighting
- Verify electrical supply for multi-module systems
- Record refrigerant charge and commissioning data for warranty compliance
- Provide end-user training on scheduling and system operation
Why ClimateWorks Recommends the R2 Series
For projects in Hampshire, Berkshire, Surrey, and Oxfordshire, the R2 VRF system is a reliable solution for complex buildings. From hotels to universities, it delivers proven energy recovery, flexible design options, and scalable capacity. Contractors benefit from simplified installation, while clients enjoy long-term comfort and performance.
Find out more:
https://www.climateworks.co.uk/commercial-air-conditioning
References
- Mitsubishi Electric City Multi R2 Product Catalogue
- Mitsubishi Electric R2 Technical Manual
- CIBSE Guide B2: Ventilation and Air Conditioning
- IET Wiring Regulations (BS 7671)
Author Bio
Dr. Julian Carter is a highly experienced thermal systems expert with over 15 years in the field, holding a PhD in thermal systems. His career spans academic research, consulting, and teaching, focusing on air conditioning and refrigeration systems. Dr. Carter bridges the gap between theoretical advancements and practical applications, providing expert insights to organisations like ClimateWorks, where his guidance informs decision-making and industry best practices. Notably, he has worked on international projects with organisations such as Daikin Industries, the International Institute of Refrigeration (IIR), and the United Nations Environment Programme (UNEP). These collaborations addressed energy efficiency, sustainable refrigerants, and advanced cooling technologies. Currently a lecturer at Edinburgh University, Dr. Carter combines his expertise with a passion for educating the next generation of engineers and advancing climate control technologies.
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