1. Institute of Energy and Sustainable Development, De Montfort University, The Gateway, Leicester LE1 9BH, UK,
2. Heschong Mahone Group, Inc., 11626 Fair Oaks Blvd, 302, Fair Oaks, CA, 95628, USA
3. Building Technologies Program, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Mailstop 90-3111, 1 Cyclotron Road, Berkeley, CA 94720, USA