Haverhill

Massachusetts, USA - Ground-source heat pump

 

Summary A standing column geothermal well heat pump was retrofitted for an original electric boiler in a public library in Haverhill near Boston. The existing air handling unit was reused for distribution of heating and cooling.   The installation of the heat pumps has resulted in a substantially reduced energy consumption and annual maintenance for mechanical equipment. Another advantage has been the reduced requirement for space for heating and cooling equipment. The seasonal performance factor (SPF) of the heat pump is about 3.5.

Building and design values

 

Building type:	Library
Location:	Haverhill, Massachusetts, USA
Year of construction:	1969
Number of storeys:	2
Heated floor area (m2):	2 600
% of total floor area (%):	No data
Design outdoor temperature (ºC)	Heating:	-22	Cooling:	35
Design indoor temperature (ºC)	Heating:	21	Cooling:	21
Degree days	Heating:	3 134	Cooling:	1 609
Base temperature for degree days (ºC)	Heating:	18	Cooling:	10

Heating and cooling

 

Application:	Space conditioning
Heat pump type(s):	Water-to-water
Heat pump installed capacity (kW)	Heating:	400	Cooling:	-
Refrigerant:	R22
Heat source	Groundwater
Details:	Six heat pumps ~ 35 kW (10 ton) each, polyvinylchloride (PVC)-80 piping in building, high density polyethylene (PE) in the earth
a) Type of ground heat exchanger:	Standing column well (2), water/refrigerant. Small (about 10% of flow for about 30 minutes) emergency bleed system stabilises temperature during extreme weather conditions.
b) Borehole depth (m):	Well depth 475
c) Pipe length (m):	Column length 4x475 = 1900
d) Heat transfer fluid:	Water/air
e) Flow rate (l/h):	No data
Distribution system(s):	Air handlers/ducts (3)
Supply and return temperature (ºC)	Heating:	50	Cooling:	11
Auxiliary system:	None
Heat pump design:	100%
Supplementary system:	No data
Heat pump system completion date:	January 1995

Performance

 

Heating energy	Heat pump	Aux. heating system	Auxiliaries1
Energy input (kWh/year):	50 000	-	Included in "heat pump"
Energy output (kWh/year)2:	No data	-	n/a

Cooling energy	Heat pump	Aux. heating system	Auxiliaries
Energy input (kWh/year):	40 000	-	Included in "heat pump"
Energy output (kWh/year):	No data	-	n/a

Additional information The total electric demand has reduced from 210 kW (old system) to 114 kW 23% reduction in total electric bills compared to the old system 65% reduction in electric bills in space conditioning alone Annual building energy savings USD 11 586

Coefficient of performance (COP)
Heating:	About 3.5
Test conditions:	Seasonal performance
Cooling:	-
Test conditions:	-

Heat pump cost breakdown
Heat pump only (USD):	Total cost USD 209 000
Installation (USD):
Capital cost (excluding heat pump) (USD):
Maintenance:	No data

Alternative system (if has been considered)

No data

Fuel cost

No data

Payback

No data

CO2 emissions

No data

 

Operational experience and other comments

Haverhill has a continental climate, with warm, humid summers and cold winters. Average space conditioning in the library is about 40 kWh/m2. Energy savings in heating and cooling of the standing column well in 1995-1996 (94 000 kWh/year) compared to the previously used electric heating and air cooled chiller system in 1993-1994 (550 000 kWh/year) are 456 000 kWh/year. The peak electrical demand of the building has been reduced by 50%.
Water-to-water heat pumps are great for commercial building retrofits, particularly when all of the distribution infrastructure can be reused. The installation of the heat pumps has resulted in substantially reduced annual maintenance for mechanical equipment and reduced requirement of space for heating and cooling equipment.

 

 

Contacts

 

Contact 1:	John Logan
Company:	Water Energy Distribution
Role:	System design
Address:	15 Wawenock Road Raymond, Maine 04071 USA
Telephone:	+ 1 207 655 7529
Fax:	+ 1 240 414 8924
Email:	geomaine @ maine.rr.com

 

 

Last updated: 1 March 2004

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