Modelling and performance analysis of a sub-dew point chilled beam in mixed mode buildings
Prompted by the energy crisis in the 1970's, European level fiscal and financial measures encourage energy efficient building design. "Mixed mode" strategies can be employed in buildings with moderate thermal loads, this approach can reduce building energy usage, and by inference, reduce C02 emissions. A mixed mode approach might employ chilled surfaces with displacement ventilation. This thesis investigates the performance and integration of one form of chilled surface design, (a sub-dew point chilled beam), within mixed mode strategies. Sub-dew point chilled beams have a surface temperature that is at or below the zone saturation temperature, this increases the cooling capacity of the chilled beam and consequently produces a latent heat transfer addition due to condensation mass transfer. This thesis describes the sensible and latent modelling approach which models the zone, sub-dew point chilled beam and mixed mode strategy thermal plant response to external disturbances. The thesis describes the use of an Enclosure Comfort Performance Indicator that acts as the objective function for the optimization of the mixed mode strategies with and without the integration of the sub-dew point chilled beam. The implementation of the Complex method for finding the operational optimums of the mixed mode strategy is described, and its effectiveness at finding the optimum solution evaluated. Normalised energy, cost and comfort performance indicators are used to assess the overall performance and integration of the sub-dew point chilled beam for different mixed mode strategies, for the ambient test conditions and for different thermal weights of building construction.