The challenges of specifying ventilation systems in commercial applications are being met with a new spin on an established technology in domestic settings.  Gilberts’ Ian Rogers explains how MVHR has been a springboard for the development of hybrid ventilation with heat recovery (HVHR). 

Today probably more than ever in the past decade we are facing huge challenges in the specification and installation of commercial ventilation systems. The recent pandemic and its impact on changing working practice and perception and the energy crisis have prompted increased client awareness of the need for effective and efficient ventilation. 

Then we have to factor in the growing consideration of indoor environmental quality (IEQ)– beyond indoor air quality (IAQ). All in an environment where more and more we are working within the constraints of existing buildings – refurbishing, refitting them to today’s requirements rather than starting with a blank piece of paper.

It all means we are all – specifiers, installers, manufacturers – having to review the conventional solutions. We’re lucky, today we have the technology via BIM, CFD (Computational Fluid Dynamics) to avoid potentially costly mistakes. The days of sitting working in a draught or getting hotter and hotter when sat by a window in the summer are (in theory) long gone. 

We can test, tweak, and validate the building services design and subject the space to be heated or  cooled to a raft of scenarios – time of year, uses, occupancy levels – before even a duct is installed.

A new twist 

The systems themselves are changing too. The commercial sector is realising the value of a system already well established in the domestic sector- MVHR- but putting its own spin on it- HVHR, or hybrid ventilation with heat recovery. 

The concept has been used in schools for years but is only now gaining traction in the commercial sector. Yet in many ways, when you look at the issues facing us, it’s a surprise it’s taken so long! It ticks so many of the boxes regarding issues facing the industry. Our temperate climate is perfectly suited for hybrid ventilation applications, with low extremes of temperature providing ample fresh cooling air even in summer if the building is designed with a hybrid ventilation in place. 

How it works

Simplistically it centres around modular stand-alone units that supply and extract the air in the internal space, balancing airflow rates and using natural air movement principles to attain air change. Fresh air is drawn in from outside, filtered and circulated at high level. The ‘used’ air is exhausted via separate chambers in the unit, with the inherent warmth of that internal air extracted via the heat exchanger and transferred to the cooler incoming air. 

Because it focusses on natural ventilation, requiring only a low energy fan as and when required to maintain the IAQ, it is low energy/low carbon. Depending on the configuration (if used as part of a building services configuration that employs PV) it can even be carbon negative!

The latest version (Gilberts’ MFS-HR) can achieve up to 75% heat recovery: imagine the impact that can make on the energy bills and the EPC. It matters: in a well-insulated building, ventilation and cooling may account for more than 50% of the energy requirement and, as of April 2023, commercial buildings had to have a minimum E rating, with B the requirement from 2030.

LPHW heat coils can be added to make the system a complete cooling and heating system, potentially eliminating the need for radiators and much of the ancillary plant whilst achieving TM52 compliance. Analysis shows that even on a cold winter’s day, the cost of running the heat unit to warm up the zone for occupancy could be as little as £2.19/room/annum. 

Cost competitive 

HVHR is cost-comparable to our conventional ventilation systems to install. Being a stand-alone system, HVHR ducting is minimised. Access for routine maintenance (changing of filters, etc) is simplified too. These considerations facilitate compliance with the latest Building Regulations Approved Document F guidance. Being modular, HVHR lends itself to refurbishment and refit projects – particularly pertinent in light of the fact that 80% of the buildings that will be in use in 2050 – the target carbon zero date – are already constructed.

HVHR is a proven system; it’s just where we utilise it that is changing. In the current light commercial sector, with the drive towards IEQ and energy efficiency, it will only grow in popularity.  

https://gilbertsblackpool.com/natural-ventilation-solutions/mistrale-mfs-fusion/