Daikin water-cooled VRV plays key role in building upgrade
A Daikin water-cooled VRV air-conditioning system has been teamed up with two Guntner adiabatic dry-air coolers to reject heat for the upgrading of the 3000 m2 4-storey building at 63 Kew Road, Richmond, the former UK headquarters of Pepsi Cola. The building is now home to notonthehighstreet.com, an online marketplace for creative small businesses.
Owned by Low Carbon Workplace, the building has been substantially upgraded to improve its EPC from E to B and to achieve a BREEAM ‘Excellent’ rating. The improved ratings also meet the London Borough of Richmond’s target for a 40% reduction in carbon emissions.
In selecting the new heating and cooling system, noise criteria and line-of-sight constraints ruled out chillers and air-cooled VRV outdoor units. Water-cooled VRV, in contrast, could be contained out of site and earshot in a plant room. The Gunter coolers on the roof are low height and low noise.
For energy efficiency, the water-cooled VRV system can recover heat within each system containing refrigerant and in the water loop.
There are six VRV systems with 13 condensing units to meet the total heating and cooling requirement and serve an air curtain in the lobby.
Another four condensers serve two air-handling units that supply tempered air at 18°C to the rear of fan-coil units throughout the building.
The building’s calculated heat load is 427 kW (peak instantaneous 348 kW). A 546 kW boiler generates hot water for the building and injects heat to the water loop as required to maintain a fixed 40°C flow to the VRV condensing units during cold weather.
The flexible and energy-efficient control strategy attains the EPC and BREEAM scores required by Low Carbon Workplace. The strategy includes PIR movement sensors to optimise conditions when people are present but to drift from the setpoint when no movement is detected and eventually switch off.
The 20% fresh air delivered to the FCUs is controlled by dampers and CO2 sensors to enhance efficiency.
There are no local controllers, and the system is controlled centrally by Daikin Intelligent Touch Managers, facilitating sub-meter of the building if it is subsequently let to multiple tenants. The system gives individual tenants the facility to control their environment through web-based access to the ITMs.