Life cycle energy and cost analysis of a net zero energy house (NZEH) using solar combisystem

In this thesis, two main house models have been developed for the Montreal, QC climate using the TRNSYS simulation software. The first is the Base Case House model which is a typical 1994 Quebec house construction that is used as a baseline for comparison. The second is the Net Zero Energy House (NZEH) model which is an energy efficient, modified version of the Base Case House containing solar technologies that capture energy (solar collectors) and produce electricity (photovoltaics). The main heating system is also modified from electric baseboard heaters to radiant floors fed by a solar combisystem. Extensive sensitivity analyses are performed on the models in order to determine the best selections for the NZEH in terms of the envelope, energy efficient technologies and solar technologies. Cost and embodied energy analyses are performed on various solar technology combinations (evacuated tube solar collector with PV and flat plate collectors with PV) in order to determine the best mix of these systems when constructing an environmentally friendly and cost effective house. In terms of annual energy use, the Base Case House requires 25,615 kWh/yr compared to the NZEH which uses 14,061 kWh/yr (before adding any solar collectors or PV modules). The most cost effective combination of solar collectors and PV modules to add to this improved house and make it truly `net-zero' is 4 flat plate solar collectors and 35.8 PV modules. A detailed cost analysis of the NZEH shows that due to the high cost of the solar technologies and the low cost of electricity in Montreal, financial payback is never achieved. However, looking at the house improvements before the solar technologies are added results in a payback of 39.3 years, and the potential to reduce that further, to 6.1 years, with some modifications to the design. In terms of the life cycle energy use, which considers the operating and embodied energy of the houses, the complete NZEH uses 63% less energy than the Base Case House and has an energy payback of 8.4 years