How GEM Works
The GEM system works by accurately monitoring the power being imported or exported and always diverts sufficient power into the hot water system in order to keep the exported power to as near zero as possible whilst at the same time ensuring that no additional power is ever imported to supply the hot water store. Priority is always given to the energy demands of the household appliances and only surplus energy that would have otherwise been exported is stored in the hot water system.
Some 'smart switching' systems can only use the full immersion power, i.e. on or off, and therefore can only save exported energy when the generated excess is over 3KW. For most days in the year excess power does not exceed 3KW even for a 4KW system. GEM is different and is able to precisely control the amount of power diverted to the immersion heater meaning that even small amounts of excess power can be continually saved and so GEM will work well with PV systems rated from 500Wp to 4KWp.
In addition to performing the generated energy optimisation functions GEM also functions as a full featured immersion timer controller with 7-day or 5/2-day operation and 3 on/off times per day together with smart temperature control enabling different temperatures to be set depending on whether the water is being heated by on-site generated energy or imported energy. This enables the cost of timed water heating to be minimised whilst maximising available free energy from the generation system. A 1-4 hour boost function is also provided.
The GEM system is simple to install and can be retrofitted to existing PV, wind or hydro micro-generation systems as well as installed with new installations.