ASHRAE Journal - November 2011 - 33

Initial Energy Efficiency Measures for GSA Retrofit Project
•	Use	existing	equipment	for	waterside	economizing •	Reenable	on-site	CHW	plant •	Turn	down	the	heating	temperature	setpoint	in	the	garage •	Replace	perimeter	FCUs	with	fewer	larger	units •	Intermittent	control	for	perimeter	FCUs •	Retrofit	FCU	fan	motors	with	ECMs •	Bring	OA	rates	down	to	Standard	62.1-2004;	use	extra	 capacity	for	economizer •	Demand-controlled	ventilation	where	not	already	implemented •	On-site	boiler	plant •	Put	two	fans	on	the	BAS	to	enable	unoccupied	shut-down •	Enable	existing	exhaust	run-around	loop	energy	recovery calculate annual energy cost savings for the EEMs. This case study gives an overview of our approach, highlighting strategies used to streamline and reduce analysis time. For some analysis details, the degree of accuracy is reduced in favor of analysis speed; a sensitivity analysis showed that this did not signiﬁcantly impact ﬁnal results and recommendations.
Location Building Parameters Space Use Occupancy HVAC System Lighting System Chilled Water Source

•	Optimize	the	reset	schedule	on	DOA	units •	Upgrade	to	enthalpy	heat	recovery	wheel •	Static	pressure	reset	control	in	AHUs •	Lower	VAV	box	minimum	airflow	rates	to	reflect	cooling	 loads •	Install	lighting	controls	at	the	circuit	level	in	section	of	 building •	De-lamp	some	HIDs	in	the	garage •	Daylighting	controls	in	lobby •	Daylighting	controls	in	perimeter	offices •	Low-flow	water	fixtures •	Software	to	manage	computer	runtime	hours	at	night •	Photovoltaic	system
Baltimore, ASHRAE Climate Zone 4A 735,300 ft2 Includes 17 Above-Grade Stories and a 1.5 Story Below-Grade Parking Garage; Late 1960s Construction Mainly Ofﬁce Space for Government Agencies 1,200 People Multiple VAV AHUs on Lower Three Levels, Two-Pipe FCUs at the Perimeter Zones in the Upper Levels, Dedicated Outside Air AHUs Provide Ventilation to the Entire Building Mainly 4 ft T8 lamps with Electronic Ballasts Purchased at About $0.30/ton·hr (2009) (Disabled On-Site Chilled Water Plant) Purchased Steam at About $21.50/thousand lbs (2009)

Analysis Process

Our premise is that the cost of the au$0.121/kWh Blended Rate (2009) Cost of Electricity dit assessment and analysis should be considered relative to the total life-cycle Table 1: Fallon Federal Building overview. value of EEMs. For a typical audit assessment, the cost of the analysis should not signiﬁcantly in- which then allowed for focused efforts and reduced time spent crease the simple payback period or life-cycle net present val- collecting information. ue of recommended EEMs. For this project, the entire analysis and reporting process took just under 300 hours of work, and Data Collection our consulting fees increased the calculated life-cycle value The data collection process consisted of three stages: 1) colof recommended EEMs by 0.7%. This time could be further lecting information before the site visit, 2) on-site information reduced through streamlined reporting. The International Per- gathering, and 3) compiling and processing information into formance Measurement and Veriﬁcation Protocol (IPMVP2) model inputs. discusses the idea of balancing uncertainty with analysis cost. Before the site visit, we requested three years of utility The Fallon Federal Building is large and has high costs of pur- bills from the building, as-built MEP drawings, and asked chased steam and chilled water, so relative analysis costs were about the possibility of starting trends at the building aulow. tomation system (BAS) that we could later collect when on We focused on increasing energy modeling speed when se- site. We were not able to obtain BAS trend data or buildlecting a modeling tool and developing the process. DOE-2.2 ing plans before the site visit. Involving the building staff with the eQuest interface was selected as the most appropriate throughout the energy audit process allowed us to gather inmodeling tool. The ultimate goal of the modeling was to de- formation more quickly, and gave us invaluable insight about termine annual energy cost savings to calculate payback peri- how the building was working and could be working. It made ods and life-cycle net present values for EEMs. Realizing that the process more transparent, and implementation of EEMs 10% to 20% error in energy modeling results is acceptable became more likely with initial buy-in from building staff. based on this goal allowed for a quicker and less detailed en- We planned each day of the site visit and ensured that buildergy modeling process; a sensitivity analysis described below ing staff had time scheduled to help. We also had a controls backs up this approach. Early in the analysis, we identiﬁed the expert on site to help with functional testing and obtaining model inputs necessary to ensure greater levels of accuracy, data from the BAS.
November 2011 ASHRAE Journal 33

Hot Water Source
ASHRAE Journal - November 2011

Table of Contents for the Digital Edition of ASHRAE Journal - November 2011
