Zero Emission Workspace has been designed to be a zero-carbon PassivHaus three storey commercial building, classified at Level 6 according to the Energy Saving Trust "Code for Sustainable Homes". Can it be redesigned to be something else?

The analysis carried out can actually be adapted to different kinds of buildings. The solution presented so far is just an example: there is nothing that stops us changing it from a commercial building to an exhibition centre, a gym or even a small high-tech residential housing development. Or we could think of something else. While a Passive House commercial building is great for businesses willing to make a concrete move towards a sustainable way of working, I would rather introduce this new building concept starting from the people. In fact, it would be excellent if potentially everyone benefited from such advanced technology.

Some possible options could be a school, a community library or a youth art centre. This way, everyone living in the area could appreciate the advantages of having a sustainable zero carbon building in their neighbourhood.

We'll go through such advantages later on; now, let's try to redo the maths for a community or educational building in general, bearing in mind that these kinds of buildings have many features in common, so it's not necessary to be too specific.

I'll keep considering a 3 storey building in order to have enough space for different kinds of activities.

As shown in figure 1, at ground floor we have an open space with a reception room and a large versatile communal area, which can be used for a number of different purposes, such as an exhibition area, a conference room or social space; a second room can be used as an audio/video media room, a reading room or a classroom.

At the first floor, a large room can host a theatre, a reading room or a big classroom and a second room can be used for visual art lessons and practice.

The third floor could feature a cafeteria, a computer lab and a painting room.

Figure 1 - Zero Emission Xspace - ground floor (click on the image to enlarge)

Figure 2 - Zero Emission Xspace - first floor (click on the image to enlarge)

Figure 3 - Zero Emission Xspace - second floor (click on the image to enlarge)

It is not difficult to anticipate the electricity consumption of such building being less than the one of a commercial building. There is no need for loads of computers in each room, for example, and we could decide to scrap some fancy advanced technologies from the project, such as the rainwater harvesting system and the electricity storage system, being confident that the amount of electricity produced by the renewable energy sources will be more than the average consumption in a year time. I would keep the electric vehicles though, since I believe that this is a mature technology that is absolutely worth including in a project like this. Maybe the fleet size could be reduced to just two or three vehicles and they can be hired by any local resident who can get a number of advantages in driving (and parking) them.

Table 1 shows a possible estimate for an art and media centre, but a very similar calculation can be made for something similar such as a school, a community library or a youth centre. For detailed comments about each estimate, please refer to the article "the office energy consumption breakdown".

Table 1 - Zero Emission Xspace, estimated electricity consumption (click on the image to enlarge or get a pdf version)

We have laptops instead of PC boxes in the computer lab and at the reception; two projectors in the media room and the computer lab; two multi-function printer/copier/fax machines, one in the computer lab, the other at the reception; two big LCD screens in the media room and in the communal room; A++ highly efficient kitchen appliances in the breakout area; a ventilation system with heat recovery as recommended by the PassivHaus standard; an intelligent lighting system; three conference audio systems; highly efficient hand driers; a CCTV system; an electric vehicles filling station.

The total consumption amounts to 70 MWh per year. This is much lower than the estimate worked out for a commercial building, which is about 120 MWh per year. That means we can be more relaxed with the size of the electricity generation system.

To cover in full the energy demand of the building, we could use a system like the one described as follows (all the figures are calculated and analysed in details in the article "how to power up a commercial building with renewables"):

or:

  • 400 Kyocera KD210GH-2PU 210W panels on a flat 600m2 roof surface, which generates about 70 MWh per year, as shown in table 1 (the estimate is given for Tolworth Broadway, Kingston-upon-Thames, Surrey, United Kingdom); this option would rule out any space on the roof for thermal solar panels
  • A Quietrevolution qr12 wind turbine, which would deliver 45-55 MWh/year

Let's estimate the annual electricity production of an array of 400 roof-mounted Kyocera PV solar panels at Tolworth, Kingston-upon-Thames, Surrey, South England (51°22'50" North, 0°16'57" West, Elevation: 25 m a.s.l.).

The parameters used for the estimation are as follows:

  • Nominal power of the PV system: 84.0 kW (crystalline silicon)
  • Estimated losses due to temperature: 7.6% (using local ambient temperature)
  • Estimated loss due to angular reflectance effects: 3.0%
  • Other losses (cables, inverter etc.): 14.0%
  • Combined PV system losses: 22.9%

The result for a fixed system (with no sun-tracking mechanism in place) with an optimal inclination of the panels of 36° is shown in Table 2 (graphical representation in figure 4 and 5 - estimates worked out using the European Commission's tool to estimate the performance of grid-connected PV solar panels).

Table 2 - Performance of Kyocera 210W solar panels at Tolworth, Kingston-upon-Thames, Surrey, UK

Figure 4 - Monthly performance of an array of Kyocera 210W solar panels at Tolworth, Kingston-upon-Thames, Surrey, UK

Figure 5 - Horizon height at Tolworth, Kingston-upon-Thames, Surrey, UK

It is clear enough that the possible combinations are many and that there isn't a good one and a bad one: what is necessary is a careful analysis of the site and the wind speed to decide whether to lean more towards solar panels or wind turbines. Other details to take into account are the investment costs required for the different technologies and the impact that some types of wind turbines may have on the landscape.

We'll call this project Zero Emission Xspace, to highlight the highly versatile and flexible characteristics of this building (X for eXpansible or fleXible).

This is a project for the people and I strongly believe that it could bring many benefits to the local residents. This modern sustainable eco-building, which will easily become a landmark in the local area, will put in action some of the most advanced construction technologies and it will demonstrate that it is possible to produce more electricity than what the building needs. It will also be created by the people for the people.

What does that mean in practice? Follow me to the next article.