Gas Vs Electric Heating from Outdoor Heating

Below is a comparison between natural gas radiant heaters and electric radiant heaters. The objective is to heat a 4.0 x 6.0m rectangular outdoor area totaling 24m2. The area in question only has one wall enclosed along a 6.0m section with a flat roof covering the entire area at 3.2m above the floor.

One 24MJ/3 Tile Natural Gas Super Ray will heat approx 8-9 Sq/m. Therefore to heat 24 sq/m a total of 3 x 24MJ heaters would be required.

One 3200W Heatstrip Radiant Panel heater will heat approx 6 Sq/m. Therefore to heat 24 sq/m a total of 4 Panels would be required.

Operating Costs

Each unit outputs a maximum of 24 MJ/h.

Multiplied by 3 units comes to a total ouput of 72MJ/h.

The consumption of one MJ/h costs around 0.015cents. Therefore 0.015 cents x 72 MJ equals $1.08 per hour.

Operating Costs

Each unit outputs a maximum of 3.2 kW/h.

Multiplied by 4 units gives us a total output of 12.8 kW/h.

The consumption of one kW/h costs around 0.165cents. Therefore 0.165cents x 12.8 kW equals $2.11 per hour.

Design Considerations

The 24MJ/3 Tile heaters have been specifically chosen for this particular area. The main reason behind this is that if the higher capacity 40MJ/5 Tile heaters were installed, customers seated closest to the heaters would be subject to excessive heat and feel uncomfortable.

As can be seen in the first diagram only
3/4 of the area is being spot heated. Ideally if there was another wall directly opposite the heaters the overall design could be changed to having 2 x 16MJ/2 Tile heaters on each apposing wall; therefore a total of 4 x 16MJ/2 Tile heaters. This layout design would be able to spot heat the entire area with even lower running costs.

Design Considerations

The 3.2m ceiling height is outside the optimum heating range for the Heatstrip panel heaters. As can been seen in the above diagram the heaters have been suspended down with dropping brackets to a more suitable height of 2.7m (500mm drop).

As can be seen in the first diagram the entire area is able to be heated. At 2.7m the heaters are able to throw/project heat a maximum distance of around 2.5 meters - almost reaching the floor. Ideally anyone standing or seated around tables will be able to absorb the heat and feel quite comfortable.