A Long Term Measurement and Annual Simulation on Domestic Hot Water Supply System

• Project/Area Number: 13650660
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Architectural environment/equipment
• Research Institution: Kanagawa University
• Principal Investigator: IWAMOTO Shizuo Kanagawa University, Faculty of Engineering, Assoc.Prof., 工学部建築学科, 助教授 (20213316)
• Co-Investigator(Kenkyū-buntansha): KONDOH Takeshi Kanagawa University, Faculty of Engineering, Research Assistant, 工学部建築学科, 助手 (90333153)
• Project Period (FY): 2001 – 2004
• Project Status: Completed (Fiscal Year 2004)
• Budget Amount: ¥3,400,000 (Direct Cost: ¥3,400,000); Fiscal Year 2004: ¥400,000 (Direct Cost: ¥400,000); Fiscal Year 2003: ¥300,000 (Direct Cost: ¥300,000); Fiscal Year 2002: ¥200,000 (Direct Cost: ¥200,000); Fiscal Year 2001: ¥2,500,000 (Direct Cost: ¥2,500,000)
• Keywords: domestic hot water supply / measurement in Residence / used hot water volume / hot water temperature in use / gas instant water heater / gas consumption / numerical simulation / ガス給湯機

Research Abstract

The aim of this research is a long term measurement and annual numerical simulation on energy consumption for hot water supply.
(1)Arrangement of a long-term measurement result : it analyzed from? survey result by establishing the calculating method for distinguishing the hot water tension of a bathtub, and reheat and automatic keeping warm of bathtub water. In one year from October,2002 to September,2003,about 20% of the whole hot-water supply consumption energy was used for reheat and automatic keeping warm, and it was comparable as the past research result in general. From the measurement result, hot-water temperature of each use of a bathtub, a shower faucet, a kitchen, and a washroom was analyzed. A remarkable seasonal difference is seen and it is necessary to continue analysis further. In examination of the method of predicting the consumption energy by reheat and automatic keeping warm, it turned out that it is greatly dependent on the heat source efficiency of a hot-water supply system, and it turned out that the same calculation modeling as the time of hot-water supply is required.
(2)Modeling and verification of a hot-water supply machine : the system of the dwelling unit for survey was modeled using the most detailed calculation model for the gas instant hot-water supply machine. Although some tuning was required, it was able to hold down to less than about 1% of error by one hot-water supply period.
(3)Annual simulation : using the calculation model of a piping system and the measurement data from October, 2002 to September, 2003, and a hot-water supply machine calculation model, the annual simulation was carried out on the same condition. Total efficiency of the hot water supply system was about 75% in gas instant supply machine.