RAINWATER HARVESTING AND ELECTRICITY SAVING ON HOUSEHOLD SCALE

Abstract

Rainwater harvesting (RWH) is an effort to utilize rainwater for various purposes, especially to meet domestic water needs. Research on this paper will look at RWH as an effort to save electricity on a household scale. The RWH method used in this study is Rooftop Rainwater Harvesting (RRWH). The research location is Natar area, a sub-district in Southern Lampung, Indonesia. A simulation involving daily rainfall data, the rooftop area of the building, number inhabitants, reservoir capacity, and volume of water demands per capita, will be undertaken to find Supporting Capacity of RWH. The simulation is applied for the houses with type 45, 60, and 70. Inhabitants of every house in this simulation are assumed 5 persons with water demand per capita of 70 liters per day. The results show, by applying RWH and using 3 or 4 years old pumps, in the wet year s houses type 45 can save electricity of 43.1%, 46.7%, and 49.5%, in a year for reservoir sizes of 2, 3 and 5 m3, respectively. With the same condition, houses type 60 and 70 can save electricity of 53.9%, 58.0%, 62.8%, and 57.6%, 63.3%, 68.7%, respectively. When analyzed from its nominal value, it seems that the KWh value of electricity savings from RWH applications is not large. But if the value is multiplied by the number of houses in a city, the electricity savings made will be significant. The advantage of saving electricity produced in wet years is 1.4 to 1.6 times from the ones produced in dry years.