Fuel Cell Network System Considering Reduction in Fuel Cell Capacity Using Load Leveling and Heat Release Loss

Abstract

In order for installation of the fuel cell system to houses or a small-scale and middle- scale building to spread, it is necessary to reduce the equipment cost. Consequently, a fuel system network (hydrogen piping and oxygen piping) and an energy network (a power transmission line and hot water piping) of distribution fuel cells are proposed [24]. In this system, common auxiliary machinery is installed in a machinery room. In this chapter, in order to reduce the capacity of the fuel cell connected to the network, a method of leveling the load is proposed. By this method, hydrogen and oxygen are generated by water electrolysis at the time of low load with little power demand, and each gas is compressed and stored. On the other hand, the stored gas is supplied and generated to the fuel cell in a period of large power load. Experimental results show that the power generation characteristics improve greatly compared with air supply, when supplying oxygen to the fuel cell [34]. Therefore, if the oxygen generated when load is small can be used for a high-load period, the installed capacity of the fuel cell can be reduced. Moreover, the heat-energy network is hot water piping, and supplies heat to each building. Hot water piping distributes heat via each building. When there is heat excess with some buildings, it can also recover this heat through the hot water piping. In a heat-energy network, the hot water temperature in a building outlet changes with the heat consumed by each building and the fuel cell exhaust heat of each building. Therefore, the heat release of the overall network differs according to the outside air temperature, the piping distance, the starting point of the hot water supply, and the flow direction of the hot water. Consequently, to counteract the piping heat release loss of the heat-energy network, the minimum piping route is examined.