One of the standard upgrades people make to their homes, at least in the temperate zone we know as the British Isles is to install central heating radiators. The system will include a nice big water boiler, these days a pricey "condenser" type that is supposedly more efficient than earlier systems, a hot water storage tank with a great deal of modern polymer insulation rather than the old lagging that its predecessor would have had. Some kind of heat exchanger within the tank, and a hefty pump to transport the secondarily heated water to radiators in each room, hopefully each fitted with a thermostat.
It has been a tried and tested and a well trusted approach to domestic heating for decades. Of course, the trendy chattering classes may well augment such a central heating system with some archaic, polluting and inefficient heating unit such as a wood-burning stove or old-fashioned range to make their residence more homely than a drab radiator panel can.
From the environmental perspective it seems wasteful: using electricity, natural gas or oil to heat water and pumping it into hollow metal panels that then radiate that heat to warm the rooms. Some people will have photovoltaic panels on their roof or even a water-heating panel up there. The payback time being about three times the life of a standard gas-fired condenser boiler, per photovoltaic panel (in the less than 100% sunny British Isles).
There are a rare few who might sink a geothermal pipe to generate hot water and some for whom wind power will be feeding their homes. But, until we all have a fully-functioning biogas-powered fuel cell that takes in kitchen and garden waste and with great efficiency fulfils all our heating and electricity needs, it seems that we're stuck with those metal tanks with the flames underneath for our heating.
But, there are innovations emerging slowly. We mentioned Elon Musk's wall-hanging rechargeable lithium-ion batteries (not entirely innovative, but neat and tidy) for storing your PV output for night time and not so sunny days. After a trip to France recently where I saw not a single photovoltaic panel on any roof, I wondered whether an alternative heating device that uses conventionally generated power, or PV power for that matter, might be more fitting than water-filled radiators.
Announcing the graphene heating pad from Xefro. Their gHS (graphene heating system) product looks set to do for radiators what the iPod did for the mp3 player. Making it more effective, more efficient and more attractive. According to the company blurb, a 1200 x 600 mm panel that is just 12 mm thick uses graphene as the heating element and saves up to 70 percent the energy for the same degree of heating you would get from a similarly sized, but obviously far bulkier and obtrusive conventional radiator. The underlying principle is that these panels are not simply air heaters as water radiators are, the heating element generates far infrared directly and that heats the people and objects in the room; this also means they're not as hot to touch, 50 Celsius, as a conventional radiator, 72 Celsius. With that improved efficiency also comes a massive saving on carbon emissions, Xefro claims. There is, of course, a mobile app for controlling your gHS remotely...and a hub controller for your network of panels and the g2O hot water system that is also available. The device works AC or DC so could be hooked up to the aforementioned Powerwall technology.
I asked Xefro co-founder Tim Harper, why graphene? "To create a smart 21st Century heater we wanted to find a material that would have a minimum of thermal mass so that it would be instantly on or off," he told me. "We also wanted a material with a high surface area so that energy would not be wasted heating up the heater. Finally, we wanted a material that we could use in a wide variety of shapes and sizes." He points out that graphene meets the first two criteria, and the graphene inks that the company uses allow them to print elements in a wide variety of sizes and configurations. "This is especially important for water heating where we wrap the flexible graphene element around a hot-water tank," he adds. "By varying the ink formulation we can change the resistivity of the heating element and its thickness depending on the required application."
It all sounds very exciting, with less energy use, more efficient heating, remote control and according to that company blurb, "Far infrared heat has been shown in external studies to ease arthritic pains, reduce tension and improve cardiovascular and respiratory conditions." I'd like to see the peer-reviewed, double-blind, placebo-controlled randomized clinical trials evidence on that, but I will go with their claims of up to 70 percent efficiency and just hope for the best with respect to any arthritis I might developing in the coming years. Just wondering if they do a decent discount for science journalists! We were due to replace our old boiler and I wasn't so keen on a trendy wood-burning stove.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the bestselling science book "Deceived Wisdom".