These are similar to performing theaters, except they may be more elaborately decorated and sound treated. With many events, there may be before- or after-performance parties held in the lobby areas, which could include dancing. There also may be crowded cocktail lounges with heavy smoking. The HVAC design must be flexible to handle these wide variations. Noise control is absolutely essential. Structure-borne noise, from improperly installed or sound-isolated equipment and piping vibration, must be avoided.
Older halls, like legitimate theaters, can be very elaborately decorated, requiring great care in locating air distribution systems. They are different from theaters in several ways. Performances are almost never continuous. Infrequently there may be a matinee and an evening performance. Most operate with a full or near-full house. There are 15 to 20 minute intermissions with the lobbies used for drinking and socializing. Background noise control is very important.
The principal areas include the orchestra (main) seating section, balconies and loges, lobby areas, ticket (box) and administration offices, and stage. Other areas include the stage manager's location, the control board area, and the dressing rooms, plus the loading docks adjacent to stages. The stage is a separate problem, which includes highly variable stage lighting. Where the hall is used for the performing arts as well, there can be intricate, delicate, and varying scenery from one scene to another, and keeping scenery and curtains from fluttering, and the main curtain from billowing when lowered is a problem.
Because of the intermittent usage, concert halls commonly experience a peak cooling load for only a few hours. A thermal chilled water or ice storage system may be an excellent application. In addition to reducing demand, the chillers may not need to operate during performances, thus reducing noise interference.
The cooling load occurring during the 15 to 20 minute intermissions or during parties, with people crowding in the lobbies used for drinking and socializing may set the design load. The density can be as much as 5 sq ft per person.
The stage area presents several separate problems. The highly variable stage lighting is a major contributor to the cooling load. Intricate, delicate and varying scenery presents air distribution problems. Artists can perform at widely varying levels of exertion. Lighting loads at stage level can be handled by exhausting air around the lights. Conditioned air is usually delivered, using numerous supply registers, from the low side and backstage with numerous return or exhaust registers at the lights. Low velocities are essential to keep scenery and curtains from fluttering.
If there is a main curtain, air balancing is also needed to avoid chimney effects that might cause it to billow when it is lowered. Spot cooling may also be needed at the stage manager's and at the control board area. Individual units are often considered for the dressing rooms, if they can't be supplied from the main air system with individual room control.
Loading docks adjacent to stages also need to be heated in cold climates. These doors may be open for long periods while instruments and possibly scenery is being loaded or unloaded. Local codes should be followed for emergency exhausts or skylights, and for fire protection and safety requirements.
Most larger halls use a central chilled/hot water system serving air handling units for each zone. As a cooling load can exist all year long in many areas, air-cooled chiller packages located outdoors are isolated from the house and its occupants, and no cooling tower with its attendant water use problems is required. Low-ambient operation controls should be supplied. Variable speed drives on secondary water pumps further reduce operating costs. Air filtration systems of 25% to 30% prefilters and 85% final filters are recommended.
If air supply is discharged at low velocity below people's seats, supply air temperatures below 65°F could create discomfort.
Recommendations/Energy Services Opportunities
- Older inefficient systems should be investigated for upgrading or replacement, particularly if CFC refrigerants are used.
- Renovate older buildings with modern heating and cooling systems, and consider adding thermal storage.
- Retrofit with heat reclaim coils or air-to-air heat recovery devices. Such recovery devices can reduce energy consumption by transferring 40 to 80% of the sensible and latent heat between the exhaust air and supply air streams.
- Retrofit "free cooling" heat exchanger in a tower/chilled water plant system.
- Add energy management systems with a central panel may allow individual air-conditioning systems or units to be monitored for maintenance and operating purposes.
Hot water is used for cleanup, dressing room showers, and rest rooms. Hot water consumption varies significantly among individual facilities. If a restaurant in included in the building, it should be handled separately.
Water heating is not a major energy user. Most water heating is done separately from the building heating system using direct resistance or gas heaters, and in some cases, point-of-use heaters.
Recommendations/Energy Services Opportunities
If existing water heating systems are inefficient or inadequate, replace with modern efficient equipment. Also add better insulation on storage tanks, or timer controls. The ASHRAE Applications Handbook Chapter on Service Water Heating publishes typical hot water use data as well as estimating procedures.
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