by Keith D. Foote
Home batteries have great potential for homeowners who want to save money, and the planet, by heating their homes with nonpolluting, renewable energy. Batteries allow the homeowner to store electricity for times when the energy source (sun, wind) isn't available, or they are using more electricity than they are generating. There is an additional plus, in that the direct current stored in the batteries can be used for electrical heat without converting it into alternating current. With modern home insulation techniques, an alternative energy home could go through a moderate winter, heated only by a combination of solar and wind power.
The same lithium-ion battery technology powering electric cars are staring to be used for homes. These batteries are just starting to be used by homes and businesses to store excess electricity generated from solar panels, wind turbines, and hydroelectric systems. Large technology manufacturers, such as Honda, Tesla, Bosch, GE, and Samsung are involved. Honda has unveiled a demonstration smart home that features a rechargeable home battery, along with an electric vehicle, solar panels and geothermal heat pump. And is controlled by an energy management system.
Flow batteries are another new way to store electricity. Researchers from Harvard and MIT have developed these new batteries. Flow batteries are metal free and rely on carbon-based molecules, called quinones. Quinones are naturally abundant, inexpensive, small organic (carbon-based) molecules. They are very similar to the molecules storing energy in plants and animals. Flow batteries store their electricity in external tanks, similar to fuel cells, instead of within the battery itself. The two basic components, the electrochemical conversion hardware, which the fluids flow through (this sets the peak power capacity), and the chemical storage tanks (these set the energy capacity), can be sized to fit the circumstances. This means the amount of energy stored is limited only by the size of the tanks. Larger amounts of energy can be stored for less cost than with traditional tanks.
Having touched on modern storage systems for electricity, it is time to move on to electrical heating. Because stored electricity comes out as direct current, it is an ideal source of energy for electrical heaters. With modern heaters becoming more and more efficient, they are fast becoming a very reasonable option for home heating. And, there is no heat loss through the chimney. Heat pumps are even better.
Electrical baseboard heating has been around for a while, and has developed a reputation for being expensive. That used to be true, but, as with other forms of hearing, they have become more efficient. When electricity is compared with the cost of heating fuels (natural gas, propane, etc.), it quickly becomes apparent electric heat doesn't deserve its long standing reputation as an expensive way to heat.
Baseboard heaters work by way of convection, taking in the cold air near the floor, warming it, and the releasing it into the room as it expands and rises. As the air cools, it sinks to the floor and is drawn back to the baseboard heater, where it is warmed again. This cycle of warming the air will continue until its thermostat reaches the desired temperature, and the heater shuts off automatically.
Wall heaters are another way to heat your home electrically. Wall heaters typically involve a fan, so part of the unit would require AC, either from the grid, or from your battery pack, per an inverter to convert the electricity to AC. As with the baseboard heating, temperatures can be set room to room, and no duct work needs to be installed or maintained.
Radiant heat from the floor means your fee are warm, and warm feet generally makes you feel more comfortable than other heating systems for a variety of reasons. It feels warmer because the heat is delivered from the floor. In-floor heating does not constantly cycle on and off, causing temperature swings, and making you feel too warm one minute and too cool the next. Nor does it dry out the air, in turn drying out your skin and nasal passages. Radiant heat is relatively draft free because there are no supply and return registers or convection-reliant radiators. Finally, the air tends to be cleaner because dust and allergens are less likely to be stirred up.
Heat pumps are remarkably efficient, and very cost effective in terms of electricity used. This is because they are not creating heat, but absorbing it from the outside, concentrating it, and moving it inside. Moving heat around is much cheaper than creating heat. In the summer months, they do the same thing, but in reverse, acting as air conditioners. For cooling, they are more efficient than standard in-window air conditioners, and cool larger areas.
The weakness of a heat pump is its upfront price. They are expensive. Also, you will definitely need alternating current to run a heat pump, meaning your alternative energy system will definitely need an inverter. However, your electrical usage will be much lower than baseboard or wall heaters would be.
Once installed, heat pumps are part of the structure (meaning they are not portable, or easily removed). There's no need to pack them away when summer ends because you'll be using them for heating. There is usually no need for additional construction to support their weight. (Window AC units often require a shelf to support their weight and to protect the window casing.)
All in all, we can expect home heating to go through a number of changes over the next few decades. Alternative energy equipment will become cheaper, and heating fuels will become more expensive.