Retrofit projects demand tailored solutions

The commercial retrofit market represents a major business opportunity for HVAC contractors and consultants. Andy Legg, Sales Director at Coolmation, 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 UK Government has committed to binding carbon targets which reduce emissions by 80% 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 rising and continue to rise steadily.

Greater demands

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.

Chillers asked to cope with these greater demands are themselves ten 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 necessarily always straightforward. The available plant room space in existing buildings is often restricted to eye-wateringly tight levels. A further spatial constraint often required on prestigious landmark buildings is the demand for the 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.

Meet the challenge

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, traders of fine 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 involved the replacement of the rooftop plant, which was more than 20 years old, with two new air cooled chillers and two air handling units.

These new chillers were specified to meet rigid dimensional and spatial constraints, fitting directly onto existing structural rooftop steelwork and below the building’s 1.5 metre parapet height.

Custom solution

Our custom-designed solution for the project utilised 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°C water leaving temperature, 12°C water return temperature and a 32°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 with the maximum height constraints of the project. The ability to have water connections on the chillers, either to the left or the right side, also made connecting the chillers to the existing pipework layout very straightforward.

Special attention was also given to energy efficiency and sound level requirements. Rhoss is one manufacturer set up to design and build units tailored for individual projects, with factory facilities that can run full Eurovent performance and acoustic tests on the specified chillers before installing them at the project. This fills the building services project team with the complete confidence they need that the chillers specified will meet the energy efficiency levels stated and the specified noise level of 63dba in open free field conditions, required on this project.

High efficiency

The components used in the Z-POWER range were specially developed to achieve high performance and energy efficiency with R134a refrigerant, delivering an EER of 3.11. The two high efficiency twin screw compressors spread the load over individual refrigeration circuits, providing greater reliability and energy savings.

The unique patented design high efficiency shell and tube evaporator, with its perfect contra-flow heat exchanger and internally finned copper tubes for increased thermal performance, are all insulated and covered with a UV resistant layer to maximise fuel efficiency. The chillers also feature an electronic expansion valve (EEV) for reduced energy consumption.

Knowing that chillers can be custom-designed 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. In working with a specialist provider, the result will be a tailored comfort cooling solution which delivers in every respect for the consultant, contractor and, most importantly of all, the client.


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