The commercial retrofit market represents a major business opportunity for hvac contractors and consultants. Andy Legg explores the particular challenges in replacing old air conditioning equipment with new high efficiency chillers and looks at how tailored chiller solutions can play a significant role in growing retrofit business.
The UK retrofit market for commercial buildings is estimated to be worth some £20 billion. As fuel prices continue their inexorable upward trend at the same time as the Government has committed to binding carbon targets which reduce emissions by 80 per cent by 2050, then improving the energy efficiency of equipment in existing buildings remains a key market driver.


There are other factors at work, especially relevant to the air conditioning sector. Air conditioning loads in many existing commercial buildings have been increasing and continue to rise steadily.

When the services for many of these properties were initially designed, it would have been difficult to predict quite how much internal heat loads would increase over the lifetime of the building. The greater use of heat generating business equipment and the installation of faster, more powerful servers demand more and more from air-conditioning systems. Many buildings were also built to accommodate far fewer employees than is now the case.

Many use R22 refrigerant

Chillers asked to cope with these greater demands are themselves 10 or more years old. Under the circumstances, they are, naturally enough, less efficient than their modern equivalents. Many of these chillers may also still be using R22 refrigerant which now requires replacement under F Gas Regulations.

Faced with this situation, it's little wonder that building owners, tenants, FM contractors and operators of chillers and air conditioning systems within such buildings should be actively reviewing the performance of their existing chillers.

However, the challenge in replacing old units with new high efficiency chillers is not always straightforward.

The available plant room space in existing buildings can be restricted to eye-wateringly tight levels.

A further spatial constraint often required on prestigious landmark buildings is the demand for the chiller or chillers to be located out of sight, in very restricted, recessed roof spaces where the units are not visible above the roofline.

In such projects, standard chillers invariably will not be able to meet these limitations nor match the performance requirements necessary to deliver an effective air conditioning solution. Instead, the answer for contractors and consultants is to work with a distributor and supplier, capable of providing specially designed and manufactured units which can be tailored to the individual needs of the project.

We have recently completed such a project at Beckett House in London, developing a solution in close partnership with consultant Mecserve and m&e contractor Mala Engineering.

Beckett House is the historic home of the Mercers of London, a trader of fabrics and silks, dating back to the 14th Century. The present Mercers Hall (Beckett House) building was constructed in 1958. The objectives for this project included replacing the rooftop plant, which was more than 20 years old, with two new air-cooled chillers and two air handling units.

The new chillers were specified to meet rigid dimensional and spatial constraints, fitting directly onto existing structural rooftop steelwork and below the building's 1.5m parapet height. Our custom designed solution for the project used two air-cooled Rhoss TCAV SZ 2320 water chillers from the Z-Power range. Each unit was designed to meet a cooling requirement of 325kW (Eurovent certified performance), at a 5.5 deg C water leaving temperature, 12 deg C water return temperature and a 32 deg C dry bulb ambient temperature.

On this project, the compressors were built alongside the condensing coils rather than underneath to ensure that the final installation met the maximum height constraints of the project.

The ability to hand water connections on the chillers, either to the left or the right side, also made connecting the chillers to the existing pipework layout straightforward.

Knowing that chillers can be customdesigned and built in this way is a significant advantage for those in building services seeking to take full advantage of the commercial building retrofit opportunity.

Working with a specialist provider should result in a tailored comfort cooling solution that delivers in every respect for the consultant, contractor and, most importantly of all, the client.

• Andy Legg is sales director at Coolmation