Thought Leaders

Designing and Constructing Zero-Carbon Emissions Houses

Phil Jones, Professor of Architectural Science at the Welsh School of Architecture, Cardiff University, speaks to AZoCleantech about how architects from the university designed and built a house with implemented technology to help reduce its energy demand and carbon emissions.

Can you explain how the concept of the ‘impossible’ house came into being?

Yes, I’m not sure it’s impossible otherwise we wouldn’t have done it! We’ve been working in this area for some time on low-carbon buildings and the idea of buildings as power stations. What we set out to achieve with this building was to demonstrate that we could achieve an energy-positive house for an affordable cost.

It’s a mix of reducing energy demand both for heating and for electrical power and then introducing renewable energy systems and energy storage; and looking at the whole thing as a system and integrating the technology together but also integrating the technology into the architecture.

How long have the architects at Cardiff University actually been working on the design of the building?

We’ve been doing research in this area for some time. The ideas have developed over time. This project actually started when we first came up with the design last summer. We started construction towards the end of last year, I think around about November, and then we finished construction early this year.

The construction process itself was about 16 weeks, if we take Christmas out. For this house, it was a quick design process because a lot of the ideas that we’ve used, we’ve been working on in one form or another over some time.

Why was this type of building considered to be improbable by the UK government?

I don’t think it’s considered improbable by the government, I think maybe what the government thinks at the present time that the cost might be prohibitive. That reflects the views of the mass house builders and they’re quite conservative in terms of changing the way they do things.

It’s more a perception that these buildings might cost quite a bit but also the difficulty of doing something new in an industry that hasn’t changed very much over the years. What we set out to show, that it is possible to do this at an affordable cost; but also with off-the-shelf technology and using local supply chains. We’ve shown that it is achievable. Whether the big house builders could as easily do it, I’m not sure because they market a different product to this.

What would you say made this project more affordable than was previously thought? I’m assuming that sourcing locally was key?

Yes, I think the affordability comes by looking at the whole design in a holistic way. Maybe the traditional approach to doing this sort of building might be to design a standard house and then bolt on new technologies.

If you take that approach, it’s always going to cost more because you have the basic standard costs plus the additional costs of these technologies. If you start with almost a clean sheet and say the solar panel on the roof that generates electricity, that can be the roof itself so we don’t construct a roof and then affix a solar panel to it.

The renewable energy system becomes part of the building component. Similarly with the wall system, there’s a thermal collector which is part of the wall construction. It’s not bolted on. Because we have the demand down, we’re heating with the ventilation system, we don’t need radiators or distribution of hot water throughout the building for radiators.

There are cost increases for certain components but there’s also cost savings. When you put it all together, we think that we can produce it for a similar cost to a standard building sight. That includes the renewable energy systems, the battery storage systems, the new heating system that we use. The addition costs of those are offset by the cost savings we can make elsewhere.

To touch on something you mentioned - the solar panel-based roof - how have you ensured the roof has remained structurally sound?

The solar panels are used a lot and they are pretty robust. The solar cells are contained within two layers of glass and the glass is in a panel system that’s then fitted to the roof. It’s the same as any glazed roof system. There shouldn’t be any issue of structural problems at all.

Solcer, a carbon positive house - Innovation in Sustainability Award 2015

Innovation in Sustainability Award 2015. Video credit: Cardiff University/YouTube

What is meant by an energy-positive house and how does this particular building meet the requirements for this?

The aim was to build a house that generates more energy from the renewable energy systems than it consumes. If you look over the whole year, then the house will export electricity to the grid more than it imports from the grid, say, during the winter time when there’s not so much sun. Overall there’s a positive-energy generation that feeds into the grid.

People can then make savings from this as well?

Yes. The renewable energy, firstly, it’s used to power the appliances and the heat pump that we use. Then it’s used to charge our batteries because we store energy for when the sun isn’t there. If there’s any excess, it goes into the thermal store so we can use it for the heating and any excess can be exported back to the grid.

We try and use as much as possible of the renewable energy in the building and only export it to the grid when we’ve used as much as possible in the building. This is looking to the future stability of the grid because we’re now being told that all this renewable energy going into the grid is causing some destabilization and there are issues associated with that which are on the supply side.

If we adopt our strategy, it takes the pressure off the grid. Firstly, it takes the demand off the grid, and our future grid may be struggling to meet demand. Secondly, it doesn’t have that destabilizing effect that, as soon as the sun comes out or the wind blows if you have wind turbines, all that energy goes into the grid. We can choose in the future when we put the energy into the grid and to some extent when we take it out.

You mentioned the ventilation system which is used to heat the building, could you explain how that works and how that helps to not need radiators?

If you can get the energy demand of the house down as low as we have through insulation and air tightness and the usual measures then the house doesn’t need very much energy to heat it. If you have mechanical ventilation and heat recovery which, again, reduces the energy demand of the house, you can heat the house through the air you put in to ventilate the house.

We have to ventilate our buildings to provide fresh air for people. Traditionally, we do that naturally by opening windows or through natural cracks that occur. In an energy-efficient house, we don’t have so many cracks, and we don’t want to open the windows and waste all that energy in the air that’s exhausted.

We can use mechanical ventilation. We provide the air mechanically to the living spaces, and then we extract from the wet spaces in the kitchen; and the heat in that air we extract is transferred to air coming in through a heat exchange.

What we do in our houses, we extract the heat from the exhaust there again with a heat pump, and we put that heat into a thermal store. The whole system is integrated. By heating through the ventilation system, we don’t need to heat through radiators. We don’t need to distribute piping around the house.

We therefore don’t need radiators. If you’re in a small house, radiators can be a problem in arranging furniture, especially in bedrooms, etc. There’s an additional benefit from not having radiators. Not only do we not have to pay for them, they’re not particularly efficient in low-energy houses - an efficient way of delivering the heat that is. Also, they have spatial implications.

Do you believe now it’s been proven that zero-carbon emission houses can be built and at an affordable rate, that this will encourage houses like this to be built in higher numbers in the UK?

That’s what we hope. What we hope to do is now to demonstrate through monitoring the performance of this house. We’ve designed it using our computer simulation models. We think we know how it’s going to perform, but we always have to test that in reality.

At the same time as we’re monitoring, we’re working with a number of interested builders and individuals now to see if we can replicate this on a wide scale. The aim is to try and get this type of approach to house building into the market.

Finally, what projects are you working on next?

We’re hoping to do more of these houses. As I said, we’re talking to a number of people about potential projects. We want to do housing at scale and maybe different versions of the Solcer house because that’s a 3-bed house. It can be detached, semi-detached, or terraced.

We would look at maybe some different sizes of houses, maybe even some sort of apartment type approach. Also, we’re discussing with various parties the same system’s approach to other building types. It could be a retail. It could be offices. It could be schools. This is the next stage to do more houses at scale but also to tackle other building types.

We also have a parallel project where we’re looking at five retrofits, whole house retrofits on social housing in Wales. That is generating interest as well because we think we can bring the cost of retrofits down to approaching an affordable level. We’re working with Registered Social and North Housing Associations and local governments on how we might take the retrofit of houses forward as well, using the same type of approach.

About Professor Phil Jones

Professor Phil Jones

Phil Jones is a Professor of Architectural Science at the Welsh School of Architecture, Cardiff University. He was Head of School between 2002 and 2013. He has a BSc in Physics (1974) and PhD in Acoustics (1977) (both from the University of Wales, Cardiff).

He joined the School of Architecture in 1977, initially as a Research Demonstrator, and in 1984 was appointed as a ‘new blood’ lecturer. He was promoted to senior lecturer in 1992, and was promoted to Senior lecturer in 1992 and to chair in 1994.

He is a Fellow of the Chartered Institute of Building Services Engineering (FCIBSE) and a Chartered Engineer (C.Eng.).

He chairs the Low Carbon Research Institute (LCRI), and led its establishment in 2008, as a consortium of six Universities in Wales, representing energy research across a broad range of subjects (Low Carbon Built Environment, Large Scale Power Generation, Hydrogen, Solar PV, Marine, Bio-energy).

Originally funded by the Welsh Government (£5.1 million), the LCRI has now over an £80 million research programme (including funding from government, UK Research Councils, EU framework and industry), involving around 130 researchers across its partner institutions.

His research area is in low energy, low carbon, and sustainable design in the built environment. Specific research topics include the development of computer models for energy and environmental prediction, urban scale sustainability, research through design and building energy and environmental monitoring.

He has led research projects in Wales, Europe, Middle East and China. Examples include the EU FP5 funded development of a web based decision making framework, Practical Evaluation Tools for Urban Sustainability (PETUS); the Strategy for Sustainable Housing in Xi’an (EU Asia Pro-Eco Programme), the building energy model (HTB2), and the Urban Scale Energy and Environment Prediction (EEP) model (EPSRC / MRC).

In collaboration with Hong Kong Polytechnic University, he developed the initial version of the Hong Kong Building Environment Assessment Method (HK-BEAM 1996) funded by the Real Estate Development Association, Hong Kong. This was one of the first of its kind worldwide and is still successfully operating in the assessment of many new and refurbished buildings in Hong Kong.

Currently he is leading two new major projects, namely, Sustainable Building Envelop Demonstration (SBED) and Sustainable Operation of Low Carbon Energy Regions (SOLCER), which alongside my other current LCRI built environment projects, add up to around a £10 million research programme.

The LCRI projects currently include, the design and construction of an affordable zero carbon house, and retrofitting 5 houses to low carbon performance. He recently completed an EPSRC grant in collaboration with the EPSRC/TSB SPECIFIC programme, to investigate energy generating building facades, and has also secured two Research Fellowships under the Welsh Government SER Cymru programme, one in the area of building energy modeling and one on plants and architecture. He has recently completed an ‘A4B’ project, working with Tata and NSG Pilkingtons, on the development of thermal solar air collectors.

He is currently an international ‘Master Academic’ adviser on the Low Carbon Buildings ‘111’ project at Tianjin and a Distinguished Visiting Research Professor at Hong Kong University. I am appointed by the Welsh Government’s to be the first chair of its Building Regulation Advisory.

I was a member of the 2001 & 2008 UK University Research Assessment Exercise (RAE), and a member of the Hong Kong RAE panel in 2006. I currently chair the COST Action (TU1104) on Smart Energy Regions (SmartER) with 28 member states (2012 to 2016). I am Chairman of the Board of Directors of Warm Wales (from 2006), a community interest company formed to install energy efficiency measures to existing fuel poor housing in Wales and which so far has delivered over a £50 million program of work.

Disclaimer: The views expressed here are those of the interviewee and do not necessarily represent the views of Limited (T/A) AZoNetwork, the owner and operator of this website. This disclaimer forms part of the Terms and Conditions of use of this website.

Alessandro Pirolini

Written by

Alessandro Pirolini

Alessandro has a BEng (hons) in Material Science and Technology, specialising in Magnetic Materials, from the University of Birmingham. After graduating, he completed a brief spell working for an aerosol manufacturer and then pursued his love for skiing by becoming a Ski Rep in the Italian Dolomites for 5 months. Upon his return to the UK, Alessandro decided to use his knowledge of Material Science to secure a position within the Editorial Team at AZoNetwork. When not at work, Alessandro is often at Chill Factore, out on his road bike or watching Juventus win consecutive Italian league titles.


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