Clutch The KTM 250 EXC-F employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates and new, nitrated steel liners. This clever design employs a diaphragm spring instead of the usual coil springs, making for considerably easier clutch action.
The difference between active and passive solar water heating systems is that active systems have circulating pumps and controls, while passive systems do not. Although passive systems are usually not as expensive as active systems and can last longer, they are generally less eficient.
Solar water heating systems use three types of heat exchangers: 1  Liquid-to-liquid. A liquid-to-liquid heat exchanger uses a heat-transfer fluid that circulates through the solar collector, absorbs heat, and then flows through a heat exchanger to transfer its heat to water in a storage tank. 2  Air-to-liquid.