How can I have a Net Zero Building?

To transform your commercial building or the place you live into a net zero building we firstly need to understand what a net zero building is.

What is a Net Zero Building?

A true net zero building is a structure that needs little to no additional energy to run in its day to day function. A building operates at net zero by ensuring carbon output does not exceed carbon input therefore eradicating the carbon footprint. This energy consumption isn’t just about the carbon emitted by the building itself but needs to account for carbon emissions through the energy supply chain to be truly carbon neutral.

Building design and technology are key in creating net zero buildings whether it be net zero office blocks, net zero universities, net zero hospital buildings, net zero homes and more.

How can we have true Net Zero Buildings?

What we really need is a building that uses as little energy as possible to get to net zero. This needs go further than the low energy building as we have them already, particularly as they still use a lot of energy. What we need is an Ultra Low Energy Building, not a ULEZ but a ULEB!

So how do we build an Ultra Low Energy Building or ULEB?

Firstly we have to look at how we use energy in a building. Obviously there is the energy of whatever we are doing in a building for example running a computer, boiling a kettle or turning a lathe. After that is the energy we use for heating & hot water, ventilation, cooling and lighting. So lets start with heating.

Energy efficient heating in a net zero building

In short, the key to using as little energy, or even no energy (yes- no energy!), is insulation and heat recovery. It is no surprise that insulation contributes towards energy efficient heating. The other big energy use to mitigate as part of the push towards net zero is warming up fresh air to replace the air we need to extract i.e. ways to control the levels of CO₂ we breath out, the humidity we generate etc.

As a means of creating a net zero building, the way we can warm fresh air for little energy use in a commercial building is through a ventilation plant.

Ventilation plants can recover up to 85% of the energy in the air we extract which of course goes a long way towards hitting net zero. The secret is then to have good control of the ventilation, so we are putting in the minimum amount of air we need to control CO₂, humidity etc. This well controlled heat recovery ventilation, coupled with very good insulation, means that our building only needs heat in the very depths of winter. The rest of the year, the heat we give out, or the heat from the computers, appliances or whatever it is we are doing, will keep the building warm enough.

Do you need help moving your commercial building towards net zero? Contact Hurtwood ltd today.

That heat recovery we talked about has other benefits and that brings us onto cooling.

Creating energy efficient cooling in a net zero building

Many buildings use chillers, which use a lot of electricity, to generate chilled water to keep them cool. The heat recovery can work in reverse in the summer, when it is 30C outside, the cooler air we are extracting from our building can cool this incoming air down.

In practical terms, as part of creating a net zero building we can spray water into the air we are extracting as part of an energy efficient cooling process. and this cools it down so we can cool down the incoming air even further. Couple this process with building mass to absorb daily peaks in building temperatures and reducing solar gain, we can reduce the energy use by our chillers to a minimum.

Then there is lighting.

Lighting a net zero building (it’s in the windows!)

With the adoption of LEDs, artificial lighting uses far less energy than it did in the past, however, it still uses energy. We can reduce the amount of energy it uses through more glazing such as windows and roof-lights, however, these have poorer thermal insulation properties so push up our heat loss in the winter and result in excessive solar gain in the summer. As a result, more energy is then used in heating and cooling than is saved in lighting.

We of course need windows to make buildings pleasant to work in but not excessive amounts. The trick to saving on lighting is tall windows spaced evenly along the facade so that light gets to the back of our spaces and good control of the lighting, not only so that it isn’t on when no one is around but also that when there is enough daylight, the lights are dimmed. 

Could it be as simple as windows to light a net zero building?

Tall windows promote good natural ventilation in the summer further reducing the electricity used in mechanical cooling. Those tall windows mean our building resembles a Georgian townhouse seen in most UK cities and towns. This is a good illustration that much of what we are talking about isn’t new, a lot of these things were figured out years ago, its often that we have just forgotten them!

Why don’t see more Ultra Low Energy Building designs today?

So if this is all relatively simple and well understood, then why don’t we have Ultra Low Energy Buildings already? Two of the seven deadly sins, Greed, developers don’t want to spend any more than the minimum and Sloth, laziness on the part of consultants and designers who don’t want to do anything different than they have done before. Ignorance however plays a big part. Clients and organisations don’t understand that buildings can actually use very little energy, they just need to be designed well and with the properly selected equipment. If we can correct these 3 and apply some academic thought to our buildings then the ULEB is a reality. Now we just need to work out how to make that happen.

Do you need helping improving energy efficiency in your building? Contact Hurtwood ltd today and gain expert insight with a free initial call.