Schematic diagram of a solar heating system used to support both water and space heating. Illustration: LGABW. Animation: Heindl Internet AG

Backup heating and water heating are the two areas in which the use of a Solar Collector, or collectors, is especially effective and economical. Used in conjunction with modern Buffer Storage devices, solar water heaters can efficiently support, or backup traditional heating systems. In the fall and spring the Heating can be entirely or substantially produced by solar energy.

A solar water heating system can cost between $ 2000 and $ 4000, which would constitute about 1 – 2 % of the cost of a one family home and even less – about 0.5 % -- of the cost of a multiple family dwelling. And at that cost such a Solar Heating System delivers up to 90 % of all needed hot water during summer months, and about 50 % during the winter – all this at zero energy costs for up to 30 years.

Batteries are needed to operate grid-independent electrical devices. The disadvantages of conventional batteries (high weight, limited performance, problematic disposal) have long been seen as principle obstacles towards an environmentally friendly power supply.

The opposite is actually true. There are numerous energy storage technologies: electrochemical (lead, nickel-cadmium, lithium batteries), electrostatic (super-capacitors), electromechanical (flywheels and compressed air), thermochemical (hydrogen fuel cells).

As air travel and mobile phones have shown, batteries can be matured and function economically. If the widespread electric stand-by or stand-alone devices were fitted with photovoltaic cells and built in batteries or super-capacitors and if customary batteries were recharged with solar charging devices (for example, a thin-layer solar module), it is estimated that in Germany alone four nuclear power plants would be superfluous.

The Block-Type Thermal Power Station at the Department of Energy and Environmental Technology of the TU Munich Picture: TU Munich

A block-type thermal power station (also called block-unit heating power plant) consists of a stationary motor which, according to the principle of power-heat coupling, or cogeneration, produces electric current and heat. The effectiveness of a BTTP is based on its use of waste heat, which in other power stations goes unused as it is discharged in a river. The high Efficiency of BTTP’s makes considerable energy savings possible. BTTP’s are fuelled by natural gas, oil, wood, as well as by methyl ester or rapeseed. Unlike solar technology, BTTP’s don’t only rely on Renewable Energy Sources, yet they do play an important role as far as optimal use of fossil fuels is concerned.

The Block-Type Thermal Power Station at the Department of Energy and Environmental Technology of the TU Munich Picture: TU Munich

A block-type thermal power station (also called block-unit heating power plant) consists of a stationary motor which, according to the principle of power-heat coupling, or cogeneration, produces electric current and heat. The effectiveness of a BTTP is based on its use of waste heat, which in other power stations goes unused as it is discharged in a river. The high Efficiency of BTTP’s makes considerable energy savings possible. BTTP’s are fuelled by natural gas, oil, wood, as well as by methyl ester or rapeseed. Unlike solar technology, BTTP’s don’t only rely on Renewable Energy Sources, yet they do play an important role as far as optimal use of fossil fuels is concerned.

Buffer, or temporary, storage makes the supply of Solar Energy possible independent of weather, time of year, or time of day. In Photovoltaics, batteries are used for this purpose while in Solar Heating systems the heat can be stored for short periods of time in a water storage tank or for longer periods in a long-term hot water storage tank.

A row of low energy houses: The balcony serves as both a collector stand and a gathering area. Picture: MBW.NRW

Through solar building methods a huge amount of energy can be saved. Passive Solar Design (windows facing south, heat insulation, etc.) alone has the potential to save up to 90 % in the cost of Heating, while the remaining heat can be produced using solar collectors. Every roof facing south is also a potential Solar Energy provider. Solar heat collectors and photovoltaic systems can be built into existing roof structures as well as be included in the plans of future Building projects. Coordination between architects and solar technology experts is an excellent basis for the highest Efficiency and living comfort. Low- or Zero-Energy Buildings face south and combine Heat Insulation, demand-oriented ventilation, and ‘intelligent’ solar energy systems. When the energy needed for heating and CO2 emissions both decline, then the standard of living will improve. Solar building is by no means a new development: the first Solar Settlements – cities which were built taking the sun’s energy into account – existed in ancient Egypt (El Lahun, 1800 BC) and in Mesopotamia (Babylon, 3500 BC).

See also: Solar Architecture, Low-Energy Buildings, Passive Buildings, Zero-Energy Buildings

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z