UNDERSTANDING YOUR BUILDING AND CLIMATE CONTROL

Evolution of climate control: evolving from fire pit to stove to boiler in basement, heat is transported through the building using water or steam

Windows, designed to let in light, also provided ventilation. Building design allowed for ventilation by including double hung windows and transoms above doors.

Electricity allowed for a constant source of ventilation with the incorporation of fans, designed to let outside air in and take inside air out. Today’s buildings are sealed from the exterior and “breathe” through their climate control or HVAC systems.

HVAC systems are designed to: remove perimeter heat gained from solar radiation

Supplement perimeter heat loss moving from the inside out

Remove heat gained from lights, machinery, and people

HVAC systems are designed to provide ventilation by moving air in and out of the building in a loop, with a percentage of air always from the outside.

It is along this loop that temperature can be raised or lowered humidity levels can be raised or lowered filtration can occur outside air can be added or removed

Most of the modification of air takes place inside the Air Handling Unit (AHU). The main components are fan, ducts, and dampers.

The fan moves the air through the ducts, and the dampers open and shut to modulate the air.

AHU often includes several components Filters are in place to keep “gunk” out of the system, control particulates or remove contaminants Heating coils in the AHU are controlled by a thermostat Hot water or steam produced by the boiler allows selected temperature to be achieved in air passing through the heating coil A humidifier in the AHU blows in steam to add moiture to the air A cooling coil/dehumidifier cools the air and takes moisture out as the air passes through

Basic components of a refrigeration system: cooling coil, expansion chiller, air cooled chiller and a water cooled chiller and cooling tower.

Mechanical systems are designed have some or all of the following capabilities: – Ventilation (outside air) is provided by adding some outside air to the stream of air entering the room. It is important to determine how much outside air enters the space. The interests of preservation and energy-efficiency are best served by ensuring that no unnecessary outside air be introduced. – Air filtration is provided by passing all air delivered to spaces through one or more filters to remove particulates. Often additional filters are added to remove gaseous components in the air. – Heating is provided to spaces by passing a stream of air over a warm heating coil and conveying that air to the space. On occasion heat may be introduced to a space directly using convectors or radiators. – Humidification is accomplished by introducing water vapor (usually steam) into the stream of air before it enters the space. Humidity can be added by the cooling coil or the humidifier in the AHU. – Cooling/Dehumidifying is accomplished by passing a stream of air over a cold coil before delivering that air to the space. If the temperature of the cooling coil is below the dewpoint temperature of the air, moisture will condense on the coil thereby dehumidifying the air. One key determinant of the preservation environment is how cold and dry the cooling coil can make the air.

Ask your facilities manager to show you the HVAC system.

A Diagram is Helpful in Understanding Zones

Sketches are also helpful

The following steps can be considered when attempting to improve the climate of a building that lacks HVAC: Reduce heat gain by covering windows to the east and west with screens or curtains to control direct sunlight. Reduce heat through the use of surrounding vegetation, such as shade trees.

Increase air circulation by taking advantage of breezes, especially to the south and north, keeping windows open but screened to prevent the entry of insects and birds. Outdoor obstacles to ambient breezes should be removed. In some cases, outdoor baffles can be erected to divert breezes through windows.

Open any vents or small windows close to the ceiling to stimulate the circulation of air through open windows closer to floor level. Enhance circulation with ceiling fans if available.

Photos and lecture based on Step-by-Step Workbook: Achieving a Preservation Environment for Collection Image Permanence Institute, Rochester Institute of Technology Climate Notebook cnbworkbook.pdf And o Cornell University Library. Preservation and Conservation. Southeast Asia Tutorial servation/meolda/index.html