Speaker - Allan Wells

This week we had yet another extremely interesting and informative talk. Guest speaker was Alan Wells, who has 17 years working in UK renewables. His talk focused on technicalities of heat pumps. As an advocate of heat pumps, he explained what is a heat pump. Simply put it is a box that sits outside your house that delivers heat.

Heat pumps supply more energy than they consume, by extracting heat from their surroundings. Currently heat pump systems can supply as much as 3kW of heat output for just 1kW of energy input. Unlike other heating systems heat pumps can also be used for cooling. They are used for commercial space heating, domestic heating and process heating but when it comes to providing hot water they don’t deliver 70°C water, more like 50°C.

Do you want a heat pump?

• Insulation and draft proof first.
• External requirements - where are you going to site the heat pump. (One metre open space, two metres wide and 30cm out from wall. Noise can be a draw back but usually minimal.
• Internal requirements - more water has flow through the heating system. Microbore pipes won’t do. 15mm pipes are required. Radiator sizes need to have higher surface area but historically spec radiators possibly okay because insulation will have been improved since radiators were installed. 

Modern houses will be challenged for space for hot water boilers. Retro-fitting heat pumps will be challenging in terms of space.

Alan felt that all new buildings should be designed with heat pumps in them.

Advantages and disadvantages 

Advantages

Carbon Footprint
Less susceptible to global markets

Long lifespan (20+ years)

Quiet

Simple to maintain

Even heating

Disadvantages

Not all buildings can be insulated well enough

Refrigerants can impact climate

Relies on government support to be cost effective

Disruptive to install

Neutral Issues

Running costs - about same is existing systems

Grid infrastructure - would not cope if everyone changed right now. 

What are the alternatives?

1. Insulation reduces the energy used
2. Hydrogen boilers (up to 20% hydrogen) - too complicated to work
3. Solar Thermal - takes load off your boiler = saving
4. Heat batteries and thermal storage (Tepeo technology) - storage type heater, advantage can work in flats. Takes advantage of cheap rate electricity periods

The club’s vote of thanks was given by PP Neil Spriddle.