Low carbon heating and cooling
May 1st 2008

With environmental issues rising to the top of the corporate agenda, owners and operators of sheds and large industrial warehouses could face problems trying to balance heating and cooling their buildings with the need to reduce their carbon footprint. Robert Simpson, Director at low carbon HVAC specialist, JET Environmental takes a closer look

Warehouses, distribution centres and large volume buildings present a real HVAC challenge.

Historically, they are not well equipped to be energy efficient. These large, drafty spaces take a long time to heat up and have often been poorly insulated, making them a peculiarly energy wasting environment. These problems have then been compounded by the energy guzzling, poorly controlled and inflexible unit and radiant heaters sometimes used to warm them.

In the face of rising energy costs, there is clearly a financial imperative for companies, many of them blue-chip corporates and multiple retailers with CSR policies and sustainability commitments, to adopt a greener approach.

The forthcoming Energy Performance Building Directive (EPBD) is a further powerful incentive to implement a low carbon solution. The aim of the EPBD is to "promote the improvement of energy performance of buildings within the community taking into account outdoor climatic and local conditions as well as indoor climate requirements and costeffectiveness".

From April 6, 2008 an Energy Performance Certificate (EPC) will be required on the construction, sale or renting out of non-residential buildings with a floor area over 10,000m2, which will include the vast majority of sheds.

So what's the answer for those organisations determined to keep their sheds warm in winter but not too hot in summer, to bring fuel costs down and reduce their the impact on the environment?

Jet air induction technology. This type of system is a proven, low carbon option perfectly attuned to sheds and other large industrial space applications. It features a series of selfbalanced jet nozzles to direct warm or cool air into the space from roof level. These nozzles are connected via ductwork to an air handling unit and selected heating/cooling source.

In many applications, which we have engineered, building owners are benefiting from fuel savings in excess of 50% with this type of system, in turn saving hundreds of tonnes of carbon per annum.

And, all this for a relatively low capital equipment cost, with little to no operational disruption, and the capability to easily reconfigure a system should the warehouse layout change over time.

The sheer size of a warehouse means it takes a lot of energy to heat. As heat rises it is typical to find the majority of the energy input to heat a building sitting in the roof void above the racking or mezzanine area. The temperature in the roof can be higher by as much as 1°C for every metre from the ground. So, for example, if you are looking to maintain your 14m high building at 16°C in winter, then the temperature at the highest point in the building can be as high as 30°C.

The most effective way to reduce the carbon footprint of the warehouse is to prevent this natural temperature stratification process by mixing the air in the space and destratifying to minimise the temperature gradient from top to bottom.

A Jet system will effectively achieve this result and capture any waste heat generated in the space, from electric lighting or natural solar gains through roof lights, mechanical handling equipment and people as well.

Cooling is becoming more and more of an issue in the UK. New building regs are making buildings more air tight and better insulated. That's fine to keep out the cold but not so good to keep a building cool in summer when there are significant heat gains from within the space. The Jet systems are designed to provide free cooling in summer by releasing large volumes of fresh air into the building and carrying out a night time purge when external temperatures are lower than the desired internal temperature.

Effective control is a key factor in optimising the performance of any low carbon, energy saving solution. Every Jet system has a bespoke controls philosophy developed to maximise the performance of the system throughout the changing seasons of the year and deliver the right internal operating conditions for people and products.

While a Jet distribution system should be at the heart of any low carbon warehouse solution, carbon emissions can be reduced further by incorporating sustainable heating and cooling energy sources. These can include solar collectors, ground source and air source heating and cooling pumps, combined heating and power sources, evaporative cooling as well as electrical energy generated from wind turbines and photovoltaic cells.

More articles from Jet Environmental: