Energy Saving Effect of Series Connection Pumps in a Building HVAC System

Abstract

The purpose of this study was to develop a new design method for piping and pumps in a HVAC system to save energy. The main focus was on pumps connected in series. In general, the energy efficiency of a pump systems is low when it operates under a partial load because current pump design methods target a maximum load. Therefore, we propose using “series connection pumps” to address the low efficiency during partial load operation. In this approach two small pumps are put in series. When both pumps are used, a high pump head is produced. When the demand flow is close to the maximum of the system, these pumps can be used with other high head pumps in parallel. When the demand flow is small, the system head also becomes small. In this case, the pump head can be reduced by using only a low head pump to reduce the energy consumption. The energy saving effect of this new method was evaluated through a simulation. The proposed method was able to reduce energy consumption to 60% or less at the valve control system and exhalation pressure control system. The method has a stronger effect on a system with long pipes or many partial loads.