A review on potential use of low-temperature water in the urban environment as a thermal-energy source

Abstract

The thermal-energy potential of urban water sources is largely unused to accomplish the up-to-date requirements of the buildings energy demands in the cities of Baltic Sea Region. A reason is that the natural and excess-heat water sources have a low temperature and heat that should be upgraded before usage. The demand for space cooling should increase in near future with thermal insulation of buildings. There are a number of options to recover heat also from wastewater. It is proposed that a network of heat extraction and insertion including the thermalenergy recovery schemes has potential to be broadly implemented in the region with seasonally alternating temperature. The mapping of local conditions is essential in finding the suitable regions (hot spots) for future application of a heat recovery schemes by combining information about demands with information about available sources. The low-temperature water in the urban environment is viewed as a potential thermal-energy source. To recover thermal energy efficiently, it is also essential to ensure that it is used locally, and adverse effects on environment and industrial processes are avoided. Some characteristics reflecting the energy usage are discussed in respect of possible improvements of energy efficiency.