Cutting heating and cooling use almost in half without capital expenditure in a previously retrofit building

Panel: Panel 4: Sustainable Energy Use in Buildings

Authors:
M. Abbas, Johnson Controls
Mingsheng Liu, University of Nebraska
Song Deng, Texas A&M University
W. D. Turner, Texas A&M University
J. S. Habel, Texas A&M University
H. Bruner, Texas A&M University
B. Veteto, Texas A&M University
Seung Uk Lee, Texas A&M University
David Claridge, Texas A&M University

Abstract

The Continuous Commissioning (CCsm - a table of acronyms used is provided following the references) process identifies and implements optimal operating strategies for buildings as they are currently being used rather than implementing design intent as is customary with most commissioning processes. It emerged at the Energy Systems Laboratory from a program of implementing operation and maintenance improvements following retrofits in buildings. The normal steps in the CC process are delineated followed by a description of its application to a large building (30,000 m2) housing classrooms, laboratories and offices on the Texas A&M University campus that was successfully retrofit earlier. This retrofit reduced cooling consumption by 23%, heating consumption by 84% and the air handling unit (AHU) power consumption by 44% in 1994, a year typical of those following the retrofit.

The continuous commissioning process was applied to the building in 1996 and this systematic examination and optimisation of the heating, ventilating and air conditioning (HVAC) systems identified and implemented numerous changes in AHU operational parameters, water loop operation, and terminal box operation, as well as identifying and correcting a number of items needing repair in individual AHU systems. This optimisation process cut combined heating and cooling energy use by another 49% without further capital investment. Individually, cooling use dropped by almost half to 36% of its original value, heating was cut by another third to 10% of its original value, and AHU use was cut from 56% to 41% of its original value in 1997.

Application of the CC process has produced energy savings averaging 20% with payback from energy savings routinely under three years and sometimes under one year.