Barkell, the air handling unit (AHU) and MVHRU specialist, has seen a considerable increase in requests for heat recovery systems.

The trend towards MVHR

Considering how the expectations for building performance and industry regulations have evolved over the last few years, and using our knowledge and experience of the commercial HVAC market, we can easily start to understand how this type of equipment has become so popular.

The push towards more airtight and better insulated buildings has compounded the need for dedicated mechanical ventilation and the introduction of the Eco-design regulation for ventilation products in 2016 ensured that most products are nowadays equipped with some form of high efficiency heat recovery device and high-performance fans and filters.

The move to achieve more energy efficient buildings will continue strong as the UK paves the road towards becoming a net zero economy by 2050 in order to tackle the challenges of climate change and its socio-economic impacts in the UK and the world at large.

Furthermore, there is no doubt the situation created by the COVID-19 pandemic will catalyse the demand for mechanical ventilation even further while also increasing public awareness about the importance of indoor air quality and, the proper control and maintenance of HVAC systems.

The product

All the above has and will continue to lead to a narrowing of the acceptable range of tolerance for the performance of ventilation products while simultaneously pushing many low performing solutions out of the market. This triage effectively facilitates the standardisation of products, allowing manufacturers to come up with solutions designed to specifically meet the needs of their customers based on current and future regulations. Considering this, it is only natural that the demand for high efficiency standardised MVHRU products will continue to increase in the future.

Heat recovery

This type of standard equipment is designed to achieve very specific functions within the HVAC system, primarily providing ventilation, fine filtration and heat recovery in a standard compact package equipped with factory fitted integral controls. When combined with other air conditioning devices such as fan coils or VRV systems on the ventilated spaces, the high heat recovery efficiency of MVHRUs means there is rarely the need for additional cooling or heating on the unit. However, most MVHRUs are also available with top-up cooling and heating exchangers to complement the heat recovery and ensure stable tempered air into the air room’s conditioning devices.

With space loads being met by the terminal devices in each room the ventilation and air conditioning systems become effectively decoupled resulting in a reduction of the overall system complexity and facilitating control. This type of decentralised arrangement also leads to the reduction of airflow requirements, leakage, duct sizes and the space required for the installation of the products. This results in overall net energy savings and, better localised control of the temperature and air quality in each zone of the building. The need for a dedicated plantroom is also eliminated since the compact size of MVHRUs means they can more easily be installed in roofs, ceiling voids or dedicated cupboards within the building. Finally, future upgrading is also made easier with the addition of a new system not requiring tampering with the existing equipment or ductwork.

But the benefits do not stop there. Their standard configuration, sizes and limited functionality ensures these products can more easily be mass manufactured resulting in quicker delivery lead times and competitive pricing when comparing them to traditional bespoke equipment. In the accelerated and competitive business environment we find ourselves in this is a major boon to all parties involved.

Factory fitted controls

The presence of factory fitted dedicated controls also helps avoid the often chaotic process of installing these on site. Due to tight budgets, it is not uncommon for customers to opt for acquiring a product without controls from a ventilation manufacturer and procure a third-party controls system to be installed on site. Without proper coordination this can result in a poor match between the systems leading to a less than optimal installation that can cause issues such as leakage, poor control and in the worst-case scenario complete failure of the controls implementation causing delays in handover and effectively negating any savings at the procurement stage.

The ‘plug & play’ design of MVHRUs ensures reliability since both the product and its controls system are tested in tandem at design stage and replicated in every single production unit. The products also become easier to specify by consultants due to their standard specification. With a ready-made, tried-and-tested solution in hand there is no need to go through the painful process of designing the product from scratch.

Availability 

Nowadays MVHRUs are available from most ventilation manufacturers as either their flagship product or as an alternative to their bespoke solutions. An efficient MVHRU will be fitted with highly efficient and compact EC fans, fine filtration and a heat recovery device in the form of a plate or rotary heat exchanger with sensible heat recovery efficiencies ranging from 73% to 93%. Options for humidity recovery, which can help reduce latent cooling loads during Summer and minimise the need for humidification in Winter, are also becoming more commonplace. 

If you consider the Therm-X range, which is Barkell’s comprehensive range of MVHRUs, it demonstrates just how wide the range of standard options can be, to meet the demands of a variety of applications and environments.

Ease of use

Like Therm-X, most MVHRU products come with a panoply of standard controls capabilities and are pre-fitted with all the sensors required to achieve effective control of the ventilation and temperature of the room. BMS communication capabilities and a dedicated, easy to use control panel, are also typically included. When correctly controlled and commissioned this kind of products can provide substantial savings versus a centralized system and yield a much more comfortable environment and user experience for the occupants.

Summary

Finally, a word of acknowledgement for bespoke central systems which still definitely have a huge role to play in the design of ventilation systems today and in the future. It is unlikely that MVHRU based decentralised solutions will ever completely replace centralised systems given their often more expensive capital and maintenance costs. However MVHRUs are surely here to stay and be another weapon in the arsenal of designers to achieve higher highs in the design of energy efficient buildings.