Combinations

The following methodology was used to allow an assessment to be made between the various technologies tested and the outcomes of their combinations. It allowed us to compare which supply mixes were the most effective in achieving a NZEB at first, and which were the best value for money, at a second stage.

Initially, we implemented all the possible combinations for our heating and electricity supply options, as presented in Figure 1. Photovoltaics were added to the existing number of 18 PV panels in groups of 6 each time, resulting in a total of 24, 30 and 36 PV panels consecutively.

Note that we have not included batteries in our combinations, since we have decided to export the surplus electricity to the grid in order to offset the deficits throughout the year. In fact, there was not incentive for using expensive and of limited capacity energy storage, while the amount of energy demands covered by the existing batteries did not make a substantial difference regarding the overall demand matching of the Visitor Centre.

After modelling all the combinations using MERIT software, the 8 most appropriate combinations for the Visitor Centre emerged, as seen in Table 1; 4 combinations for a Net Zero Site Energy Building and 4 for a Net Zero Source Energy Building.

In both cases (Site and Source NZEB), there is one combination for each of our heating supply options.

The benchmark for reaching these best 8 combinations for the Visitor Centre was the electricity supply to be greater than but as close as possible to the electricity demand, in terms of Site Energy and Source Energy respectively.

Finally, these best 8 combinations were incorporated into a comprehensive Energy and Financial Analysis.