2016 ASHRAE Winter Conference

The use of solar photovoltaics (PV) to provide comfort cooling will be presented.  The cost of solar PV installations has fallen, making the solar electricity competitive.  This discussion will cover techniques to best apply solar PV energy to cooling loads.  The "total solar cooling efficiency" of different methods will be compared for both solar PV and solar thermal.  Specific applications, i.e., PV driven air conditioning and heat pumps, energy storage, load mismatch, and PV with energy efficiency, will be discussed.  The shading effect of roof mounted PV arrays on HVAC systems and building loads will also be discussed.

While photovoltaic (PV) electric generation can be used for any type of load, peak generation often coincides with building cooling needs.  This presentation demonstrates how buildings with different types of mechanical systems match the PV output on an hourly daily, monthly and yearly basis.  Based on this data, a discussion on what it would take to get these buildings to net zero energy and  to the considerably more challenging goal of creating a micro-grid by adding an energy storage device and disconnecting from the utility.  The economics of PV cooling will be compared to the thermal cooling technologies.

Unitary rooftop equipment is commonly used for cooling in low-rise commercial buildings.  As PV module prices have dropped, feasibility of using solar for reducing purchased electricity has improved.   The simplest systems are utility-interactive.   There is a good coincidence between solar power availability and air conditioning power requirements since solar gain and outdoor temperature are inputs to building load.   Many low-rise commercial building have significant available roof area for solar PV arrays.  These relationships support the idea of using solar PV to  drive rooftop air conditioning equipment ito reduce purchased energy and the electrical demand on the utility grid.

Double-skin’s solar PV integration has been illuminated as a cost-effective HVAC refurbishment for worldwide implementation. The second facade as a glass skin is well suited for implementing PV elements. The presentation review: mathematical modelling of PV integrated double skin’s facade’s buildings physics (including construction structures relevant heat and mass transfer phenomena, energy conversion processes and balances); related HVAC’s cooling and heating dynamics and loads calculation method development; as well as prediction of PV electricity production and HVAC (including cooling) energy demand satisfaction via building’s performance co-simulation (coupling the CFD simulated air-flow within the double skin’s facade and facade/building energy simulation).