Outline of the Analysis

To suggest how caravans can achieve carbon neutrality, analysis involved four areas: heat flow out the external floors, heat flow in the radiators and radiator pipes, hot water pipe flow and pressure, and renewable energy solutions. By implementing these changes and producing clean power, improving insulation, using suitable materials, and installing energy-saving appliances, caravans can become ‘off-grid’, reducing costs and the carbon footprint. The static caravan architype analysed has a standard cuboid exterior shape with a gable roof, and inside usually compromises of 1 main bathroom, 2 bedrooms, and a open plan kitchen and lounge area.

Energy Losses from Pipes and Walls

To carry out this analysis, assumptions are made from the temperature inside and outside, to specific heat transfer coefficients, to wind speeds. From analysing the caravans’ windows, the difference between single and double gazing is sizeable, with head flow of 439W and 78W respectively. This equates to a potential cost saving of over £500 per annum. As for the roof of the caravan, analysis was carried out to compare the heat loss with and without insulation and results showed that insulation reduced the head flow from over 1200W to just 114W. For the rest of the walls and floor in the caravan, the heat flow equated to 272W.

Assuming that a central boiler heats water for radiators in all the rooms of the caravan to replace the heat lost, the total length of these hot water pipes and then heat loss values could be calculated, before and after a 50mm polyethylene insulation. The energy saving of using this insulation equates to £343 per annum showing the importance of having insulated pipes even in a small-scale habitat such as a caravan.

Appliance Energy Consumption

Using standard appliances commonly found in a static caravan, such as a fridge, kettle, power shower, and oven, can collectively result in a significant amount of energy consumption in a single day. It is estimated that the total energy used amounts to just over 8 kWh, excluding the boiler's consumption. This estimation is based on assumptions regarding the boiler's 60W pump running for 5 hours per day, as well as the average hot water energy consumption, which is calculated based on heating 122 litres of water from an average inlet temperature of 15^oC to 55^oC, resulting in an overall output value of 19 kWh per day.

Figure 2. Average wind speeds in the UK by LPA

Achieving Carbon Neutrality

After minimizing energy consumption from the boiler and other appliances, the total daily power consumption is estimated at 27kWh. Given the size of the roof, it is assumed that 20 solar panels, each with a capacity of 250W, could be installed, providing 5kW of power, which equates to around 20kWh per day.

However, the remaining 7kWh could be supplemented by using a mini wind turbine, particularly advantageous for static caravans located in coastal areas with high wind speeds. It's noteworthy that even the lowest wind speeds in the country are around 6m/s (13.4mph). Assuming the turbine blades have a radius of 1.5m, or a 9.84 foot diameter, this specification of turbine could produce 8.5kWh of energy per day, effectively covering the remaining excess energy consumption.

Naturally, daily energy usage will vary, and the output from solar and wind sources will be weather-dependent. Nonetheless, this analysis demonstrates that achieving carbon-neutral habitation in static caravans is a feasible goal.