Heating of Spaces : Calento SLG

Calento SLG : Solar Air Heating of Spaces

The Calento SLG solar air collector was designed to provide warm air to the space even under the harshest Canadian climate. On cold, sunny winter days, the collector delivers warm, free solar-heated air into the building or process, thereby saving on gas or electricity, year after year.

How the Solar Collector Works

General Function in Recirculation

Function with outside air

Function with Additional Heating Source

Technical Data

Technical Sheet

Calento SLG	SI Units [IP Units]
Technical Data
Solar air collector type	Flat-plate glazed, closed loop
Working fluid	Air only
Main use and purpose	Space air heating
Peak solar efficiency, rated	65 %
Maximum power output	650 W/m² [206 BTU/hr per ft²]
Maximal air throughflow per collector surface	90 m³/h per m² [5 cfm/ft²]
Pressure drop @ maximum throughflow	400 Pa [1.6 in H₂O]
Maximum temperature rise above ambient	60 °C [108 °F]
Absorber panel
Panel material	Aluminum alloy 99.8, Temper H18
Absorber thickness	0.7 mm [0.028 in]
Available colors, selective	blue, black
Absorbtivity in thermal spectrum	95 %
Emissivity in thermal spectrum	<3 %
Polycarbonate cover
Thickness	40 mm [1.6 in]
Panel width	500 mm [20 in]
Panel length	not limited
Panel structure	7 walls, 6 cavities
Thermal resistance	1.1 W/m²/°C [0.19 BTU/h/ft²/°F]
Light transmissivity	65%
Standard color	clear
Mounted collector system, on site
Overall collector depth	10 – 30 mm [4 – 12 in]
Weight per surface area, including framing	5 kg/m² [10 lbs/ft²]
Internal mount structure	Zee’s and hats, 18 ga. steel
Outer framing	extruded aluminum
Maintenance requirement	none
Freeze protection	unnecessary
Overheating protection	unnecessary
Ratings & certifications
Solar Rating Certification Corp. certificate no.	SRCC 10002148
Solar Keymark certificate no.	011-7S3114 L
Test laboratory	Fraunhofer ISE, Germany

Performance of the Solar Collector

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Description

The SLG is a closed-loop collector. The air is typically drawn in from the bottom, led through the panel to collect the sun’s heat and delivered into the building space at a higher temperature. Even on a sunny, but cold (-20°C) winter day, the Calento SLG still will deliver warm above the space setpoint.

For engineers: Trigo Énergies’s first design objective is to offer a collector that delivers useful solar-heated in on the coldest (often the sunniest) days of winter. To achieve that, the SLG is covered by a 7-wall polycarbonate with a lowest thermal transmittance of 1.1 W/m²K while boasting a very respectable light transmittance of 65%.

The result is that on cold, -20°C sunny days, the collector can still deliver warm solar air back into the building or process. In summer, air remains still in the collector, ready for the next call for heat. The Calento SLG can also be fitted with an outside air intake and be used as an outside air preheater.

For architects: The outside cover of the Calento SLG is made of vertical, multi-wall polycarbonate panels that interlock into each other. The entire wall area covered with the Calento SLG ends up being an even and smooth vertical surface, with a silky, slightly translucid look. The inside of the collector, including heat panels and framing, comes standard with a dark blue color, originating from the physical vapor deposition solar-coating process.

The polycarbonate panels are co-extruded with a protective film to safeguard them against exposure to ultra-violet radiation, extending their life and performance with natural ageing. Framing is designed to allow the thermal expansion and retraction.