The above graph shows power consumption (the upper line graph, denoted in Watts) plotted against occupancy levels. The premise behind U-CARE is that heating and cooling can be programmed according to predicted occupancy figures as modelled from past data. It is hoped that this model will result in energy savings. The data above clearly shows that there is no correlation between energy consumption and occupancy levels. A fundamental project expectation was that energy draw would be lower during higher periods of occupancy, since reduced heating levels would be required. This expectation has not been upheld by the data which indicates that heating/cooling is not triggered by ambient temperature. This proves great scope for improvement. So, will basing heating and cooling on predicted occupancy levels generate energy and cost savings?
One limitation of the metering data is that the BMS (Building Management System) does not facilitate the identification of when energy consumption is being used for heating and when it is being used for cooling. One of three scenarios is probable therefore – 1) the energy draw is primarily used for heating; 2) the energy draw is primarily used for cooling; 3) a mixture of heating/cooling is in operation, which could be rationalised as the two are essentially cancelling each other out within short time intervals.
This brings us to a third source of data from the U-CARE project – questionnaire responses. Users of Graham Hills 634 were invited to provide feedback on their comfort levels within the lab in relation to the existing heating/cooling settings, via an online questionnaire. Initial analysis indicates that the majority of users report that they are frequently too cold within the facility. This finding suggests that cooling is frequently operational and that it may account for the fairly steady power draw irrespective of the number of users in the room. Could it be therefore that current cooling levels could be cut? If it transpires that cooling is not in fact operational on a regular basis, accounting for the steady power draw, the conclusion will be that increased heating levels are required – this will definitely not result in energy savings!