Paul Braithwaite talks to Andy Brown, director of Midtherm Engineering, about natural ventilation, how to grow and diversify and be at the forefront of a business which is still in its infancy.
Andy Brown, sales director of Midtherm Engineering, smiles easily. But then he has plenty to smile about.

Midtherm designs and installs natural ventilation, natural lighting, flues, chimneys and commercial kitchen canopies - and it is motoring. Brown will enjoy this analogy as he loves fast cars.

There are 26 employees of the company plus there are several specialist sub contractors he can call upon at any time which means there are usually six or eight teams of installers on the road at any one time.

And, he insists, all Midtherm kit is manufactured by the group, delivered to site and installed by either direct labour or the dedicated sub contractors, which are all fully trained and hold the relevant certificates.

There are two other directors of Midtherm Engineering, John Walsh, managing director, and Ray Andrews.

Andrews is the chairman of the group and has a stake in several companies. It makes fans, kitchen canopies, flues and natural ventilation products, and even has a laser profile cutting company to assist with the growing demand.

Andrews leaves the day-to-day running of the company to Walsh and Brown. Brown says the pair are driven by the will to run a successful company.

Turnover trebled

The Midtherm group manufactures all its own equipment. It turns over some £17.4 million. Turnover has trebled in the last 10 years, he says. And this means, says Brown, while Midtherm Engineering has a relatively small turnover compared to the group, it is part of one of the biggest manufacturers and installers in the UK flue market.

Midtherm Engineering began in 1983 as a contracting company. It, too, has trebled its turnover in the last 10 years. And in the last 18 months the engineering arm has taken on 20 per cent more staff to cope with the demand.

The growth has come, in part, from a deal in 2006 with Hamworthy boilers. Midtherm Engineering has taken over the flueing for all its boiler installations. The initial contract was for three years and the partnership is into its second term. All flue work is passed to the Midtherm/Hamworthy department for tendering, manufacturing and installation.

It makes sense, says Brown, because it means Hamworthy can concentrate on what it does best - making boilers - and Midtherm does what it does best. But Brown was at pains to add it will fit flues for any make of appliance. But he admits flues are not being marketed as hard by the company as the array of natural ventilation products.

It is good, solid business and the mood seems to be natural ventilation and natural lighting. It is becoming more popular and the company is concentrating on its portfolio in this sector. Brown is pretty proud of the fact he was instrumental in the first natural ventilation project for the company in 2001 and the business has grown from there.

'It was a job for North Tyneside Council and once we got it, we had to design, manufacture and install the vents.'

Its Windvent and Litepipe products are, he says, naturally driven solutions to the complex modern ventilation problems.

Midtherm has co-operated for the last three years with Sheffield Hallam University in designing and testing its products. 'The university tested all our products and collated the results for us,' says Brown.

Sizing package

Hallam University has developed a computer-aided sizing package for the company which has proven to be a success.

The university has also helped design a new blade for the X-stream which was launched recently at Eco-build.

The blade has been designed to provide the most efficient air movement giving 20 per cent less airflow resistance than traditional 45deg pitched louvre blade designs.

Brown says this means when comparing the new blade with the bench mark standard 45deg louvre blade, there is a 45 per cent increase in occupant-comfort level and 42 per cent reduction in trailing edge stall pressure.

At Eco-build, Midtherm shared a stand with Solatube, the company which sells the natural light products which are used on Midtherm projects where necessary.

Brown also talked about mixed mode cooling, especially where there were massive heat gains from computer servers or rooms where there were lots of computers and ancillaries. Both natural ventilation and air conditioning have a place, he admits.
And, he insists, Midtherm's sales team would not force natural ventilation if it were necessary to have air conditioning. But 'sometimes there has to be a compromise'.

'First, air conditioning is going to cost more throughout its life cycle. Take a school, for instance, there are probably only a couple of weeks in July/August when the temperature maybe uncomfortable for pupils, then they break up for the summer holidays.'

Brown adds that for nearly all of the term time natural ventilation is adequate. And this even extends into the comms room or classrooms where there are many computers.

Midtherm has the Solarbreeze airflow terminal which is, essentially, a passive stack ventilator but it can be extended with either a Midtherm Solatube (natural daylight system) or Solastar fan unit (a fan driven by either an electrical supply or a small solar PV unit) which will drive in fresh air or extract used stale air.

'There is a vast heat gain from having many computers, scanners, printers etc and if it needed a couple of cassettes, then we would not say otherwise. However, natural ventilation certainly lightens the load for most of the time, whether it is installed in halls, dance studios, classrooms, corridors or office based rooms.

'We would have a CFD (computational fluid dynamics) model to determine the heat load of each individual room with the given size of the terminal to find out whether natural ventilation would work efficiently or whether it would need back-up assistance because of excessive heat gains.'

However, he insists, natural ventilation works alone but it does depend on the location and area of the room within any given building.

'There are different ways of tackling a problem. For instance, there might be a need for trickle vents in the windows or low level vents with the cool air coming in and rising as it mixes with the warmer air to be sucked out via a Passive Windvent terminal situated at roof level.

'However if the wind is in the wrong direction, a balanced Windvent stack is the right choice rather than relying on the prevailing wind to enter at low-level.'

Brown says it is all a question of how many air changes are necessary for a given area to allow a comfortable environment and ensure warm stale air is removed.

Wind movement

Midtherm has done its research about wind movement. He maintains that on average only one or two days a year does not have any wind movement at low level.

And the higher you go the better the wind speed, in general - which is why natural ventilation works best with the units mounted on the roof and the air being forced down into the building based on aerodynamic principles.

'With air being ducted down through the acoustically lined trunk and into a building, you have a fresher environment to concentrate on your future.'

There is even a sophisticated intelligent control system, The X-StreamMID2012, which regulates the ventilation and control temperature, air-quality, humidity and CO₂ level. Connection to other BMS system is possible via Modbus RTU comms.

'The teacher does not have to open windows or push buttons. It is automated by sensors which modulate the damper position situated at the base of the stack.

Midtherm Engineering has been heavily involved with the Building Schools for the Future initiative, working with main contractor's and companies like NG Bailey on Newcastle-under-Lyme College, Burley College, the Swindon Academy and currently Midtherm is working at Hameldon College, Burnley.

Enhanced knowledge

'Our design and install knowledge of natural ventilation in schools has certainly been enhanced by these and other projects,' adds Brown. He sees natural ventilation as virtually in its infancy.

'We are researching a number of new products at the moment. Some have already being tested by BSRIA. We are spending heavily in this sector devolving new and exciting products.

'We are at the start. We need to progress and diversify as the market changes. There are different trends and we want to be in the forefront of those changes.'

Brown wouldn't be unhappy to grow the business by 50 per cent in the next five years.

'It can be done,' he believes 'with the right attitude, drive, commitment and determination this will be achieved with the continued support of the team, this is why we are naturallydriven.co.uk'.

For more information visit: www.naturallydriven.co.uk