Yale Energy Guideline

Thermal energy for most buildings in the Central and Science areas of the Yale campus is produced in the Central Power Plant. The Sterling Power Plant serves the Medical School Area and Yale New Haven Hospital. Steam and chilled water produced in the plants is distributed to the buildings in underground tunnels or in direct buried pipes. Electricity is either purchased from the utility company or generated in the Central co-generation plant and distributed for the central and science areas of the campus.

Optimum use of energy is controlled by Direct Digital Control systems in individual buildings, and monitored by a Central Building Utilities Metering System. Energy conservation is an inherent part of the control and monitoring systems.

The following is a tabular representation of the University standard temperatures, relative humidity (RH) and central air handling unit operation policy.

Yale Standards for Space Heating and Cooling
	Summer Occupied	Summer Unoccupied	Winter Occupied	Winter Unoccupied	Winter Recess	Relative Humidity	Air Supply
Dormitory	N/A	N/A	70-73^o F	65-68^o F night setback	60^o F T-setback	N/A	N/A
Classroom	73-78^o F	HVAC-Off Temp. Uncontrolled	70-73^o F	65^o F night setback	60^o F T-setback	N/A	Summer Unoccupied Off
Offices	73-78^o F	HVAC-Off Temp. Uncontrolled	70-73^o F	65^o F night setback	60^o F T-setback	N/A	Summer Unoccupied Off
Laboratory As req'd	73-78^o F	78-80^o F night setback	70-73^o F	65^o F night setback	60^o F T-setback	50% RH	Summer/Winter Unoccupied setback
Library	73-78^o F	78-80^o F night setback	70-73^o F	65^o F night setback	60^o F T-setback	30-50% RH	Summer/Winter Unoccupied setback
Book stacks	70^o F	70^o F	68^o F	68^o F	68^o F	50% RH	On
Assembly/ Dinning Hall, etc.	73-78^o F	HVAC-Off Temp. Uncontrolled	70-73^o F	65^o F night setback	60^o F T-setback	N/A	Summer Unoccupied Off

Production and distribution of energy

Steam is produced in the power plant burning either natural gas or oil with maximum efficiency and minimum pollution. It is distributed underground to the buildings where it is used for either direct heating, for re-heating of hot water for heating, and use in the showers, bathrooms, etc., or as process steam used in the kitchen, laboratories, etc. Steam releases its energy (in radiators, heat exchangers, etc), and is returned to the power plant as the most efficient feed water for the boilers, since it retains it's thermal energy (120-180^o F), and is chemically treated.

The University's energy conservation effort is focused on optimum utilization of equipment for steam generation, optimum production of steam in the boilers as well as on maximum return of condensate to the power plants.

Chilled water is produced in the power plant with maximum efficiency using either electricity or steam. The production is optimized utilizing the available equipment in the most economical way to meet the actual load of the campus. The chilled water supplied to the buildings is 42^o F in the summer and 44 deg F in the winter, and is at sufficient pressure and flow to meet the cooling demand of the buildings.

The University's energy conservation effort is focused on optimum utilization of equipment for chill water production, optimization of chill water supply temperature, optimization of the cooling tower operations, and optimization of chill water pressure.

Electrical energy for the Central and Science areas of the campus is generated in the Central Power Plant, which is a co-generation plant. The local utility company services the Medical School area. The co-generation plant generates normal power as well as back-up power. Both are distributed to the individual buildings.

The University's energy conservation effort is focused on optimum utilization of generating equipment and minimization of energy purchases from the utility company.

Steam, chill water and electricity is distributed from the plants to the buildings. Each building is individually metered and billed for energy usage. The building users and occupants have access to the building utilities metering system's data via the web.

Here is the web address: http://pub-max.facilities.yale.edu/Maxweb

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