CO_2ヒートポンプ給湯システムにおける運転条件のロバスト最適化(実測給湯需要量を用いた検討)

摘要

家庭用給湯における省エネルギー化を目指して，近年自然冷媒としてのCO_2を用いたヒートポンプによる給湯システムが開発•商品化され，要素性能の向上によりヒートポンプの成績係数(COP)は大幅に増大した.一方，ヒートポンプだけではなく貯湯槽も含む給湯システムを年間を通して運転した場合のシステム性能も，重要視されるようになってきた.%The daily performance of a CO_2 heat pump water heating system with a hot water storage tank is affected by the history of daily hot water demand and heat pump operating conditions. It is important to estimate the values of daily performance criteria accurately and determine the operating conditions properly. In a previous paper, a robust optimization method based on the minimax regret criterion is proposed to determine the operating conditions so that the estimated system efficiency is maximized subject to the lower limit for the estimated volume of unused hot water under uncertain hot water demand. In this paper, the proposed method is applied to a case study using a measured monthly hot water demand, and its validity and effectiveness are ascertained through a numerical study.