A Method for Simultaneous Optimization of Energy Demand and Energy Supply in Buildings

This paper deals with simultaneous optimization of the building energy performance from both building and system design points of view. The majority of the researches conducted on building energy demand reduction and energy supply optimization, treat demand and supply sides separately. Firstly, the demand side parameters are analyzed for demand reduction and then the most suitable configuration for the primary energy conversion is investigated. The relationship between the building energy demand and supply may not be well understood when they are analysed sequentially instead of simultaneously. This paper investigates the potentialities of an integrated building demand-supply energy optimization method that will provide a solution to whole building energy efficiency problem. The method is based on the Extended Building Energy Hub (EBEH) concept which is an evolution of the Building Energy Hub (BEH) method. In the BEH approach the vector of energy inputs, the energy supply fluxes, is related to the vector of energy outputs, the energy demand, by a coupling matrix. The coefficients of this matrix are functions of the efficiency of the various energy conversion systems and of the distribution of energy fluxes onto the energy converters. In the EBEH method, demand side building design parameters will also be included to coupling matrix and will be evaluated together with primary energy options. This way the for instance, demand side parameters (U values, window-to-wall ratio, etc.) will be contrasted to the opportunity to use solar energy for electricity production in terms of primary energy savings and the optimum configuration will be calculated. The paper introduces the basic principles of this approach. Moreover, a preliminary practical demonstration is developed through the application of a simplified procedure to a case study of an existing building.