Compensation for differential energy balance across a building incorporating solar energy systems

In order to compensate for imbalance in solar energy between different sides of a building, and the resultant difference in energy availability and (heating/cooling) demand, methods using offsetting were developed to adjust occupiers’ energy bills. In the case of solar electricity generation, a model was considered, in which all the power is routed through common meter(s), so that total electricity generated is recorded. Equal proportions of this metered energy can then be deducted from occupiers’ individual meter readings, to give the net energy use for which each user is billed. Computer-based models were used to calculate the imbalance on those energy demands, which are affected by solar gain, i.e., space heating and cooling. The offset was calculated, such that all users pay the same bill for a given thermostat setting, and are charged more or less, for settings which result in higher or lower energy consumption respectively. Several case studies were performed, in which one building parameter was changed between successive trials. It was found that the offset was different in each case. Therefore, it is necessary to calculate the offset separately for each location, and for each building, depending on those parameters related to solar and thermal energy exchange.

Research highlights▶ Unbalanced PV power across a building is offset by routing power via common meter. ▶ Imbalance in solar gain causes an imbalance in heating or air conditioning demand. ▶ The imbalance is a function location, climate, building envelope, etc. ▶ Implementation of offsets is achieved through the owner/occupier's smart meter.