WELD HILL, Arnold Arboretum Laboratory (In Construction) (MEP: Cosentini, Well Designer: Alderson Engineering, Well Design Review: Image Engineering Group, Well Driller: Geothermal Services Inc.)

This project will be Harvard's first closed loop (vertical) system. (From The Weld Hill Institutional Report): "In a 'closed loop' system, BWSC water will be used to initially fill the piping network; and the system will not involve on-site withdrawal or discharge of groundwater. This system would consist of approximately 60-70 vertical 'wells,' each being approximately 500 feet deep. Each 'well' is a 4 inch diameter borehole, in which a loop of extremely durable plastic piping, with a U-bend at the bottom, is inserted and grouted into place. The type of system that is proposed for the Research and Administration Building typically involves 6 to 12 'wells' connected together to form a circuit, which can be isolated, before the multiple circuits are joined together before entering the building. The 'wells' are spread about 15 feet apart. Since no water is actually being withdrawn (or added) to the 'well,' these are simply boreholes into which the plastic piping is inserted."

 

TYPE	WELLS	DEPTH	PUMP CAPACITY (gpm)
Closed Loop	88	500'	2 - 340

 

 

BYERLY HALL (In Design) (Geothermal Consultant: Water Energy Distributors, Inc; Well Driller: Dragin Geothermal Well Drilling, Inc.  Architect: Goody Clancy; MEP: Cosentini) Currently Under Construction

The ground source heating and cooling system being installed as part of the renovation of Byerly Hall is the second such system for the Radcliffe Institute.  The project team has been able to apply lessons learned from the Radcliffe Gym system, such as disinfection requirements and possible bleed requirements, to the new Byerly system.  Byerly will have a hybrid well system – 4 wells will be used as typical standing column wells.  The fifth well (well #3) will be used as a discharge well for any necessary bleed water from the other wells.  This will prevent bleed water from being discharged to storm drains.  Water injection tests have been performed on well #3 to ensure that it can absorb the more water then would ever be necessary for bleed.

TYPE	WELLS	DEPTH	PUMP CAPACITY (gpm)
Open Loop	5	1500'	450

 

46 BLACKSTONE (2006) (MEP: Arup)

This system, for cooling only, is driven by 5-hp VFD pumps. Together the wells supply 2 dual-stage water-to-waterheat pumps, for a total capacity of 90 tons of cooling. The Blackstone system's COP is 5.8, significantly better than the 2.80 allowed by ASHRAE 90.1 for an air-cooled chiller.

 

TYPE	WELLS	DEPTH	CAPACITY (tons)	# PUMPS	PUMP DEPTH	PUMP CAPACITY (gpm)
Open Loop	2	1500'	60 total	5	100'	90

 

 

90 MOUNT AUBURN (2006) (MEP: Cosentini)

 

Ground water is pumped from the wells to 5 ClimateMaster GLW-360 water-to-water heat pumps and then returned to the wells using Goulds 60 Hz high capacity submersible pumps. A direct digital control system turns the heat pumps on and off in the appropriate mode (cooling or heating) to maintain design temperatures in the heating and chilled water accumulation tanks. The speed of the well pumps is modulated by variable frequency drives to match the cooling and heating loads of the buildings. The hot water and chilled water distribution pumps use with variable frequency drives to reduce pump energy. The heat pumps produce heating hot water and chilled water, which is circulated through coils of the fan-coil units, ventilation unit and conservation unit.  Each heat pump is individually valved from the primary loop on the building side to a hot water accumulation tank and a chilled water accumulation tank, providing chilled water and heating hot water year round. Cosentini Associates Inc. calculated lifecycle costing for geothermal, using an electric boiler (a standard centrifugal chiller/cooling tower with electric heat) as the baseline. This project received $73,000 in NSTAR rebates, saves $35,380 annually, and has a 5.6-year payback (Y2006 dollars).

TYPE	WELLS	DEPTH	CAPACITY (tons)	# PUMPS	PUMP DEPTH	PUMP CAPACITY (gpm)
Open Loop	3	450', 550', 650'	110	5	100'	120

 

 

RADCLIFFE GYMNASIUM RENOVATION (Summer 2005) (MEP: SEi)

 

The two wells consist of an outer-steel casing (apx. 60-70 feet long), from the ground to the top of the bedrock. Inner steel casing is installed from the ground surface to between 420 to 425 feet below the ground surface. The wells supply 3 water-to-water heat pumps for a total capacity of 63 tons.

TYPE	WELLS	DEPTH	PUMP DEPTH	# PUMPS	PUMP CAPACITY (gpm)	CAPACITY (tons)
Open Loop	2	1500'	100'	3	80	63

 

 

QUADRANGLE RECREATIONAL ATHLETIC CENTER (2005) (MEP: Consigli)

 

The wells supply three water-to-water heat pumps for a total capacity of 63 tons. There is one 30-Ton and two 10-ton ClimateMaster heat pump units. The 30-ton ClimateMaster unit was replaced in 2006. During the replacement minimum flow switches were installed in the well water lines to prevent running the heat pumps with insufficient water flow, which could lead to freezing when the unit is in heat mode. R-22 refrigerant is used.

TYPE	WELLS	DEPTH	# PUMPS	PUMP DEPTH	PUMP CAPACITY (gpm)	CAPACITY (tons)
Open Loop	2	1500'	3	100'	90	60

 

 

ZERO ARROW STREET (2004) (MEP: Allied Engineering)

 

The office area on the fourth floor of the building is served by earth-coupled water to air heat pumps. A central air handler with hydronic coil serves the theatre. The coil is fed by a pair of water-to-water earth-coupled heat pumps. All of the heat pumps are served by a common building loop. The loop is passed through a heat exchanger to maintain separation of contaminants. The heat exchanger is connected to three SCWs, each with a dedicated pump. The building uses ClimateMaster Genesis GR/GS Series pumps. This heat exchanger transfers heat into the building in winter and removes it in the summer. The Owner expects a 5-7 year payback on the system.

TYPE	WELLS	DEPTH	# PUMPS
Open Loop	3	1500'	3

 

 

ONE FRANCIS STREET, Walter Lippman House, Nieman Foundation (2002)

 

The system at the Nieman Foundation has been in operation since its renovation in 2002. The columns supply thirteen water-to-air heat pumps.

TYPE	WELLS	DEPTH	# PUMPS	CAPACITY (tons)
Open Loop	2	750', 850'	13	50

 

 

Ground source heat pumps use the relatively constant temperature of the earth (approx. 50 degrees F) to heat or cool a building by circulating fluid or groundwater from the ground into the building, as illustrated below (from Geo4VA). There are two types: closed or open loop systems. In cooling mode, the earth acts as heat sink as heat is pulled from the building and released into the ground. In heating mode, the earth is a heat source as the fluid absorbs heat from the ground and circulates it through the building with heat pumps. No boiler or cooling tower is required, which improves aesthetics and reduces sound.

For more information on Ground Source Heat Pumps, see a presentation compiled by Harvard University Operations Services departments Environmental Health & Safety, Facilities Maintenance Operations and Harvard Green Campus Initiative: Ground Source Heat Pumps at Harvard: Lessons Learned (2007). The PDF contains:

• Part I: Are GSHPs Good for Harvard?
• Part II: How GSHPs Work
• Part III: Lessons Learned from Current Campus Installations, and Recommendations

 

For regulatory requirements, see the Massachusetts Department of Environmental Protection fact sheet on Ground Source Heat Pumps.

 

Harvard's Department of Environmental Health and Safety summarizes geothermal permitting information specific to Harvard buildings and lists recommended geothermal permitting consultants.

 

 

 

Ground Source Heat Pump Cooling and Heating (from Geo4VA)

 

 

Geothermal Energy Association

U.S. Department of Energy Geothermal Technology Program

Geo4VA

The International Ground Source Heat Pump Association (IGSHPA)

National Ground Water Association (NGWA)

 

36, 38, 40 CONCORD STREET (Radcliffe Bunting Quad)

SIZE (Btu/h)	ACTUAL EFFICIENCY
Heat Transfer Munchkin Boiler 208,700 (at 38 Concord St) 400,000 (at 36 and 40 Concord St)	94%

 

 

Condensing boilers are a proven technology, and many are already in use on the Harvard campus. The principal efficiency gain comes from the capture of heat from the exhaust gases. As the name implies, exhaust gases are condensed, which in addition to greatly improving efficiency, also reduces exhaust requirements. Munchkin boilers installed at Radcliffe require only a 4” PVC exhaust pipe that can be run out the side of the building instead of the roof because the exhaust temperature is reduced to 90 degrees Fahrenheit.

EnergyStar boilers have an Annual Fuel Utilization Efficiency rating greater than 85%. See EnergyStar's information for boiler and contractor recommendations.

 

Exceed ASHRAE 90.1-2004 or local energy code, whichever is stricter, and meet ENERGY STAR criteria.

The American Council for an Energy-Efficient Economy lists the efficiency of specific heat pumps and air conditioners, listed by CEE category.

They also provide the Online Guide to Energy-Efficient Commercial Equipment.

 

ASHRAE 90.1-2004 Minimum Efficiency Requirements

 

Table 6.8.1F (page 49) Gas and Oil Fired Boilers

 

Equipment Type	Size Category (Input)	Subcategory or Rating Condition	Minimum Efficiency
Boilers, Gas-Fired	<300,000 Btu/h	Hot Water	80% AFUE
		Steam	75% AFUE
	≥300,000 Btu/h and ≤2,500,000 Btu/h	Maximum Capacity	75% Et (thermal efficiency)
	>2,500,000 Btu/h	Hot Water	80% Ec
	>2,500,000 Btu/h	Steam	80% Ec
Boilers, Oil-Fired	<300,000 Btu/h		80% AFUE
	≥300,000 Btu/h and ≤2,500,000 Btu/h	Maximum Capacity	78% Et
	>2,500,000 Btu/h	Hot Water	83% Ec
	>2,500,000 Btu/h	Steam	83% Ec
Oil-Fired (Residual)	≥300,000 Btu/h and ≤2,500,000 Btu/h	Maximum Capacity	78% Et
	>2,500,000 Btu/h	Hot Water	83% Ec
	>2,500,000 Btu/h	Steam	83% Ec

 

 

Advanced Buildings Minimum Efficiencies

Table 2.5.4 - Boilers > 300,000 Btu/Hr:

(from Benchmark 6.5: Mechanical Equipment Efficiency Requirements)

 

 

 

Condensing boilers are preferable because they include an additional heat exchanger to transfer heat from the exhaust to the incoming water. Secondly, water vapor produced by burning the fuel condenses back into liquid form, releasing latent heat. Condensing boilers are used widely in the United Kingdom.

 

For more information, see:

UK National Energy Foundation: Modern Central Heating Boilers

Condensing Boiler - Wikipedia

Comparisons of different boiler systems available in North America on the Natural Resources Canada website

 

ONE OXFORD STREET: McQuay Centrifugal Chiller – A team from Harvard Engineering and Utilities, led by Senior Engineer and the Project Manager, Anthony Casello PE, PMP, replaced two chiller units that were approaching the end of their life-expectancies. These chillers function as a part of the 13,000-ton Central Chilled Water Plant at One Oxford Street. The Central Chilled Water Plant provides chilled water to almost 70 buildings throughout the Harvard Campus, spanning from Holyoke Center to 60 Oxford Street.

The E&U team thoroughly considered their options, meticulously studied the current and future cooling loads and reviewed proposals from a number of vendors to choose the most appropriate replacement that would meet the cooling demand while maximizing the energy and cost savings potential. And the resulting chiller installation is truly state of the art. The energy saving features of the two new chillers include medium voltage motors with variable speed drives. The Oxford Street plant is one of the first to combine these two features on a large tonnage chiller. The combination of these technologies is so new on the scene among large tonnage chillers that this installation is the second for York International. The general improvements in chiller technology as well as the operational features specifically engineered into these machines will achieve these cost-savings and reductions in environmental impact for the university:

• Eliminate the use and storage of R-500 refrigerant at the plant (a type of refrigerant no longer being produced due to its ozone-depleting properties)
• Reduce the plant’s annual energy usage by 10% (approximately 2,500,000 kwh)
• Reduce the plant’s annual electricity costs
• Obtain financial incentives through NSTAR rebate programs

According to Casello, One Oxford is saving over $300,000 a year by using these high-efficiency chillers.

See the HGCI Spring 2007 newsletter for more information and a description of the process.

 

ONE WESTERN AVENUE: Evergreen Chillers –175 ton Hermetic Centrifugal Chiller and Filtrine Coolants; 15650 Refrigeration Specifications

 

Centrifugal chillers are highly efficient. They have improved controls and condenser sections and compressions for removing heat and discharging it to the outside air. Pacific Energy Center has developed CoolTools™, an integrated set of tools for design and operation of chilled water plants.

 

Use zero-CFC refrigerants.  See a scientific study of refrigerants for LEED. The U.S. Department of Energy Federal Energy Management program provides product recommendations and calculators to aid in selecting a chiller system.

The American Council for an Energy-Efficient Economy lists the efficiency of specific heat pumps and air conditioners, listed by CEE category. They also provide the Online Guide to Energy-Efficient Commercial Equipment.

Exceed ASHRAE 90.1-2004 pages 31 - 58, or local energy code, whichever is more stringent. See ASHRAE 90.1 Minimum Efficiencies for Centrifugal Chillers.

 

Advanced Buildings Minimum Efficiencies

See Advanced Buildings Appendix D for Centrifugal Chiller Efficiency Tables.

 

Table 2.5.5 - Chillers

(From Benchmark 6.5: Mechanical Equipment Efficiency Requirements)

 

Equipment Type	Size Category	Required Efficiency - chillers with or without ASDs		Required Efficiency - Chillers with ASDs Operational Compliance Path
		Full Load (kW/ton)	IPLV (kW/ton)	Full Load (kW/ton)	IPLV (kW/ton)
Air cooled w/condenser Air cooled w/o condenser	All	1.2	1.0	N/A	N/A
	All	1.08	1.08	N/A	N/A
Water cooled, reciprocating	All	0.840	0.630	N/A	N/A
Water cooled, rotary screw and scroll	<100 tons	0.780	0.600	N/A	N/A
	≥100 tons and < 150 tons	0.730	0.550	N/A	N/A
	≥150 tons and ≤ 300 tons	0.610	0.510	N/A	N/A
	>300 tons	0.600	0.490	N/A	N/A
Water cooled, centrifugal	<150 tons	0.610	0.620	0.630	0.400
	≥150 tons and ≤ 300 tons	0.590	0.560	0.600	0.400
	>300 tons and ≤ 600 tons	0.570	0.510	0.580	0.400
	600 tons	0.550	0.510	0.550	0.400

a. Compliance with full load efficiency numbers and IPLV numbers are both required.

b. Systems with single chillers that operate on 460/480V require ASDs. ASDs are optional in multiple chiller systems.

c. Water-cooled centrifugal water-chilling packages that are not designed for operation at ARI Standard 550/590 test conditions (and thus cannot be tested to meet the requirements of Table 2.5.5) of 44* F leaving chilled water temperature and 85*F entering condenser water temperature shall meet the applicable full load and IPLV/NPLV requirements in Appendix B., Tables 1-6.

 

Table 2.5.6 - Absorption Chillers

 

Equipment Type	Required Efficiency Full Load COP (IPLV)
Air cooled, single effect	0.60, but only allowed in heat recovery applications
Water cooled, single effect	0.70, but only allowed in heat recovery applications
Double effect - direct fired	1.0 (1.05)
Double effect - indirect fired	1.20

 

 

Before replacing a chiller at Gutman Library, the Graduate School of Education hired an engineer to create a heating and cooling load model for the building to ensure that all equipment specified would meet building needs, without being oversized. This model also allowed the GSE to see how different project and equipment options would affect the building's cooling capabilities and energy costs/project repayment outlook. The Graduate School of Education replaced a 300-ton chiller and associated cooling tower with a 215 high efficiency York chiller and new Marley tower.  The chiller came equipped with a variable frequency drive, and both pieces of equipment were selected for their efficiency ratings.

 

Anthony Casello, Project Manager for the One Oxford Street Chiller Replacement Project, stresses that there is a huge benefit to upfront planning with a project like this. The E&U staff of electrical and mechanical engineers dedicated their time and effort to the essential background work – the modeling, monitoring of loads, analyzing of the operations of the system, data collecting and analysis, and reviewing of innovative technologies through an in-depth bid analysis, in order to fully understand which technology would best meet the operations demand in the most efficient and effective way.

Anthony stresses that “applying solid project management practices – in the planning/programming phase of the project – in combination with sound engineering and extensive modeling, ultimately led to the decision to utilize medium voltage VFD’s on this chiller replacement project” and is truly to credit for the associated achievements. “The first thing we did was set up basic parameters for the new equipment (voltage and capacity) and then contacted the major chiller manufacturers to understand and identify what they had available. Once we felt we knew what was out there in the market place, we used that information to develop an extensive RFP document with detailed performance specifications that we felt would best serve our plant. When the bids were received, they were evaluated using sound engineering and a lot of detailed modeling to determine which machines would provide the most cost effective and reliable solution for our plant.”

In this way the E&U team’s professional commitment to this thorough assessment serves a critical role to the university. Anthony highly recommends that other university facility staff contemplating similar projects should invest in data collection and analysis and utilize that information “in combination with sound engineering and project management practices ” to fully understand what will have the most cost-effective and environmental benefits. “In the end, it was the extensive history of operating data that is collected as part of E&U’s continuous effort to improve operations in combination with the team’s commitment to detailed engineering and careful project planning that led to the successful identification of the best option.”

For the Gutman project, pre-project engineering and building modeling allowed the GSE to select the best equipment for the job and to accurately compare the value of multiple project options. When first approached, the GSE was not aware of efficiency opportunities within its facilities. Thinking back to efficiency improvements it had made in the 1990s, administrators felt they had done all they could to maximize building efficiency. However, with ongoing and rapid changes in building technologies, facilities should be audited every few years to ensure building systems are keeping pace with technology upgrades.

 

U.S. Department of Energy Federal Energy Management