Green Building Demonstration Project Adam Saling City of San Diego

Green Building Demonstration Project

Adam Saling

City of San Diego


• Built in 1981, bought by the City of San Diego in 1994 after two years of vacancy

• Wood and stucco construction with “marblecrete” exterior

• Offices for Environmental Services Department and Field Inspection Division

• 3 floors with 2 wings totaling 73,000 sq. ft.


Original HVAC and Lighting Equipment

• 70 water source heat pumps (EERs of 10-11)– Cold water from cooling tower is cooling source– Hot water from gas boiler is heat source– Used R-22 as refrigerant in compressor

• Package units used to condition lobby• 2 roof top cooling towers with 15 hp fan

motors to release heat• No centralized controls• Conventional T-12 lamps, magnetic ballasts


Project Scenario

• Needing code related upgrades and repair of mechanical and electrical systems

• Office layout needed to be modified• Inefficient, old, poorly maintained system• High energy consumption costs

– Total electric energy consumption $.096/kWh, $1.98/sq.ft., or 20.6 kWh per sq.ft., corresponding to $145,700 annually


Project Challenges

• Goal of four year simple payback in terms of energy savings

• High levels of energy & environmental performance called for within ESD’s strict financial budget

• Overall stringent objective to reach less than 9 kWh per sq.ft. annually for electricity use

• This “green building” will be a model for sustainable building practices in San Diego


Other Project Challenges

• Persuading decision makers to approve• Modeling (DOE-2) and integrating

incremental energy efficiency measures• Procurement of upgraded equipment

– Low bid vs. Sole-source purchases

• Dealing with low-bid contractors regarding alternate “equal” products, per contract provisions


System Solution

• New, more efficient cooling towers• More efficient water source heat pumps• Lobby package units replaced with water

source heat pumps• Occupancy sensors installed• Direct digital controls installed

– Building Automation System– Automatic Temperature Control

• Lighting improvements coincident with project


Water Source Heat Pump Replacement

• New EERs of 14.5-15.2 (versus 10-11)• New heat pumps consume 17,250

kWh/month, versus 28,750 KWh/month of old heat pumps, saving 138,000 KWh per year

• Total savings of 40% or $15,180 per year• Refrigerant R-22 still used in compressor


Other HVAC System Changes

• Cooling towers replaced– With open type, slightly oversized fiberglass

towers with 5hp fans – Produce 75% energy savings

• Variable speed drives installed on all pump motors

• Isolation valves on all heat pumps• Reduced supply air & outside air

– Improved air filtration with 85% bag filters


Lighting Improvements

• Full task/ambient lighting improvements– Full lighting controls with dimmable electronic

ballasts, T-8 lamps, photocells, and occupancy sensors– Provided lighting power of .73 W/sq.ft. (compared with

California Title 24 allowable 1.5 W/sq.ft)

– Light levels maintained– Work station lighting supplemented with low-power task lights

with occupancy sensor

• Total energy savings– 53% energy savings from original lighting


Other Building Load Reductions

• Occupancy sensors– Installed for lighting & interlocked with heat

pumps to shut down heat pumps in unoccupied zones

– Installed for computer monitors with time usage sensors

• High performance spectrally selective window films installed– Block heat, let light in

Green Demonstration Building Project

Resulting Electricity Use, 1996-97

• Used 8.0 kWh/sq.ft, meeting 9kWh/sq.ft. goal!


Resulting Gas Use, 1996-97

• Used 3000 therms per year, for $2421


Integrated Energy Savings

Purchase &Installation

Cost ($)

Base(kWh/ft2 /yr)

Savings(kWh/ft2 /yr)

TotalSavings

($)

Paybackperiod(years)

High Efficiency Heat Pumps 15,000 17.10 1.25 13,673 1.10New Lobby Heat Pumps 10,250 7.41 0.11 1,398 7.33

New Cooling Towers 57,000 7.59 0.18 1,674 34.05VSDs on Pumps 18,100 14.50 2.98 14,879 1.22

Reduced Supply & Outside Air 0 15.84 1.06 7,084 0.00Light Fixture Revisions 40,100 10.43 1.63 13,099 3.06

Lighting Controls 45,500 8.81 0.82 6,706 6.78Occupancy Sensor Interlock 5,100 14.78 0.28 2,075 2.46

CRT Occupancy Sensors 21,000 11.45 1.01 5,935 3.54Window Films 46,000 7.99 0.40 3,851 11.94

Panels in Sloped Glass Offices 9,700 11.52 0.07 758 12.80Total $267,750 71,131 3.76


Financing Structure

• Capital Improvement Program within the Environmental Services Enterprise Fund

• SDG&E provided services and financial support– Environmental efficiency measures, outside professional fees,

and financial incentives totaled over $300,000– Provided displays and educational material on energy

efficiency in the building

• EPRI provided matching funds for energy consultation fees of about $75,000

• $130,000 savings from manufacturers participating in the Partnership Program


Project Timeline

• Less than 2 years to completion


Project Results

• Energy efficiency measures cost ~ $270,000• Utility savings of ~ $70,000 annually• Overall payback of 3.8 years• Demonstration facility for other SD area projects• Projected increase in worker productivity• Award winning environmental design (AIA in SD)• Educational benefits, including training facility,

environmental displays, project video & building monitoring

Documents

Green Building Demonstration Project Adam Saling City of San Diego