Air conditioning solutions that improve thermal comfort in the workplace

At BSE Ltd, we are specialists in engineering design and build of a whole range of mechanical, electrical and plumbing (MEP) services. We keep up to date with the latest technology and are well placed to give our clients the best advice available.

Johnston Logistics, one of Irelands leading transport logistics companies, commissioned us to evaluate and redesign their head office air conditioning system as part of a refurbishment and new build. We stepped up to the challenge with confidence. The brief was simple, design an energy efficient system that will provide a comfortable, draught free environment to work in with good temperature control and clean fresh air. Our client was conscious of their responsibility to the environment and keen to conform to the f-gas legislations and the EN378:2016. These regulations are becoming ever more difficult to meet by restricting the amount of refrigerant that can be used in a system and the mandatory installation of refrigerant leak detectors.

Their existing air conditioning system wasn’t fit for purpose and preformed unsatisfactory as the occupants continually complained about thermal discomfort and stuffiness. The existing air conditioning equipment did exactly what it was designed to do, heat and cool but what was lacking was an understanding of the basic design fundamentals.

When we design an air conditioning system we assess all options to see which system is best suited to the application and the client’s budget. Our design process allows us to look at all design options and assess which solution is best suited to our client’s requirements. As part of our design protocols we look at new innovated energy efficient concepts, one which interested us was the Mitsubishi Electric City Multi Hybrid VRF (HVRF).

The HVRF which allows for simultaneous heating and cooling is a 2-pipe system. The system uses a refrigerant between the outdoor condenser and a Hydro BC controller (HBC). Water is the medium between the CMB-WP108VGGA1, HBC and the PEFY-WP63VMA-E indoor units. The system acts like a combined water chiller and low temperature boiler with the benefits and energy efficiency of a VRF heat pump.

This is the first application of a HVRF system in Ireland in an office environment and was the ideal solution for this client. It allowed for a straight forward, quick and neat installation which was paramount due to a very tight schedule of the project. It also allowed the client to meet the EN378 legislation and avoid the need to install leak detection sensors.

So, we finally have a product where we have better control of the flow and return water temperatures and supply “air off” temperatures which allow for improved comfort levels and eliminates cold draughts – see graphs 11 to 13 . Our design engineers were keen to work with this concept as it merges all the reliable traditional technologies into one neat system i.e. boilers, chillers and controls system.

We also installed several R32 refrigerant PEAD-M1000JA ducted units and MSZ-AP50VGK, R32 refrigerant high wall split units. We were really impressed with the low noise levels suitable for any small office and the Wi-Fi connectivity allowing freedom to control the units while out of the office.
To achieve high levels of energy efficient heat recovery, while meeting the demands of fresh air and humidity control within the workspace we installed several Mitsubishi Electric LGH-100RVX-E Lossnay mechanical ventilation systems.

Our project goal was achieved with great success and the clients comfort levels were met beyond their expectations.