(116d) A Portable Solar Farm House

The performance evaluation of a portable house is investigated by harvesting of solar electric and thermal power from a photovoltaic (PV) solar wall. A prefabricated outdoor room was retrofitted with solar ventilation and solar photovoltaic technologies to replace part of electrical and thermal load of the utility energy supply. The experimental investigations were conducted to generate electric and thermal power from a photovoltaic solar wall. A full scale portable solar farm house test facility equipped with a photovoltaic solar wall was set up at Concordia University, Montréal, Québec, Concordia. The portable outdoor room was having interior length of 3962 mm and an interior width of 2896 mm, with a total interior floor area of 8.61 m² and a height of 2825 mm. The experiments were carried out on photovoltaic solar wall fixed on the wall of a portable room, which was inclined at 10° East of South on the horizontal plane.

A photovoltaic solar wall in a portable house was constructed with a pair of glass coated photovoltaic modules forming a parallel plate channel with a plywood board and connected to a rheostat of variable resistance up to 50 Ω [1]. A rheostat was a wire-wound circular coil with a sliding knob contact, was used to vary electrical resistance across connected PV modules without interrupting the current. A photovoltaic solar wall was assembled in components: (i) two commercially available glass coated PV modules; (ii) air passage with air-gap width of 90 mm; (iii) insulation panel; (iv) side walls made of Plexiglas and wood; and (v) connected wooden frames. Only wood was used as duct and piping material for construction of the photovoltaic solar wall. The photovoltaic solar wall was constructed with two PV modules (989 mm X 453 mm). The insulation panel was thermally insulated with plywood board covered frame filled with polystyrene for minimising any heat transfer between the air passage and portable room zone.

The outdoor tests were conducted for obtaining currents, voltages, temperatures, air velocities, sensible heat, thermal time constants and thermal storage capacity of glass coated PV modules installed on a wooden frame. The current-voltage measurements were obtained for determining electric power output with a series electrical circuit connection of a pair of vertically inclined PV modules installed on a wooden frame. The temperatures were measured as a function of volumetric capacity viz., height of a photovoltaic solar wall. The non-linear thermal results include measurements of temperatures for PV modules, insulating panel and ventilated air column in the wooden frame. The air velocities were developed in the ventilated air column for transportation of heat both as a measure of buoyancy and fan induced hybrid ventilation.

The Montréal Island being surrounded by Sárasvatî Nadî (Sanskrit: सरस्वती नदी; English: Saint Lawrence River; French: fleuve Saint-Laurent) and with presence of great lakes around its region, it has cushioning affect of latent heat storage in its environmental parameters. It is having short summer having temperature of 24.76 °C with 235.48 cooling degree-days, and prolonged winter with temperature of –13.02 °C with 4574.95 heating degree-days. It has 303 sunny days with 2029 hours of sunshine. The atmospheric pressure is 101.54 kPa with wind speed of 14.29 km/h. The water vapour pressure is 0.29 KPa in winter and 1.64 kPa in summer. All data is based on year round average basis [1]. The Heating, ventilating and air conditioning (HVAC) requirements were met in a portable house by a baseboard heater, an induced-draft type exhaust fan and a split window air conditioner [1]. The heating was supplemented by conditioning from the fresh air entering from the inlet damper through photovoltaic solar wall installed on building façade. However, during the mild season for the duration of conducting experiments, neither baseboard heater nor air-conditioning unit was used for auxiliary heating or cooling inside the outdoor test room.

Reference:

[1] H. Dehra, “A Numerical and Experimental Study for Generation of Electric and Thermal Power with Photovoltaic Modules embedded in Building Façade”, submitted/unpublished Ph.D. thesis, Department of Building Engineering, Concordia University, Montréal, Québec, Concordia, August 2004.