Martin Luther King Jr. Civic Center
Sustainability - Heating and Cooling

"During the day, new natural ventilation shafts will help to remove warm air and draw cooler air in from outside. Exposed concrete ceiling joists will provide thermal mass to reduce peak heating loads and smooth out temperature swings during office hours."

— City of Berkeley, 1999

The primary heating system is a hot water boiler with baseboard distribution, and the primary cooling is natural ventilation. In addition, a split system is used for the computer room, and a couple air-conditioning units are used for penthouse conference rooms.

The distribution units are perimeter panel radiators, which heat 60% radiatively, and 40% convectively.

It's a great benefit that this is a massive building. The seismic upgrade component of the renovation work added mass as well.

There was a critical change made related to the building form, even though it's a renovation project. Floor plans were changed to be more open by eliminating several smaller spaces. This was the biggest change that improved the ventilation. Also, thermal mass was kept exposed on the interior, and ventilation towers were cut into building to provide enhanced stack effects.

Arup used proprietary software for comfort and natural ventilation studies, and specifically, to size the openings in the vertical ventilation shafts.

No advance performance modeling and analysis was done, and Arup didn't do post-occupancy HVAC performance measurement and verification. The Berkeley labs did some measurement and verification. Performance monitoring CBEE showed more than 80% satisfaction, though technical comfort parameters were outside the formal comfort criteria (ASHRAE 55-1992).

Details

Permanent Monitoring System: The building monitoring system (BMS) is barebones for control rather than simple monitoring. It only tracks temperatures, and controls fans and the boiler. The hot water boiler is turned on and off based on outside air, which seems to provide better control than following interior thermostats.

Lighting: Efficient light system

Lighting controls: Separate lighting control system

Window controls: Light at the janitorial station to tell them to open the windows for night ventilation. BMS determines this. First experience with this and is recommending it on other projects.

What unusual constraints did you have to work with that differed from non-green projects (material selection, site features, etc.)?: Normal penetration issues through heavy seismic elements. Going with no air-conditioning.

Renewable and Green Energy: Considered PVs but budget did not allow.

Have you had other designers/owners/engineers approach you with questions about this building?: Yes, the Center Built Environment has. Every once a while people call.

How did you determine what electric lighting levels were needed in spaces that made use of daylighting?: Only did mechanical. Fixture and layout decisions were on them and IES standards.

How did you determine what levels of natural/window ventilation were available relative to what was needed: Relied on their software. Number of fixed openings is double above T24 guidelines.

Did the owner/architect/engineer have any ideas that you talked them out of? What were these ideas and why did you feel they wouldn't have worked?: Had a good collaborative effort.

Did the owner/architect/engineer convince you to try any ideas that you were hesitant about? What were these ideas and what were your initial concerns?: No air-conditioning, and naturally ventilating the building.

Were you nervous about any particular mechanical system components' ability to perform adequately (ie. Reduced HVAC capacity due to greater thermal performance, use of natural ventilation, mechanical lighting configuration, etc.)?: Definitely the no air-conditioning and natural ventilation.

What unique frustrations did you experience working on this project?: Piping through and around seismic systems. No window operators, or solar control film, expose more thermal mass.

What aspects of this project did you think went the smoothest?: everything.

Did you feel there was enough coordination/communication between the architecture and engineering teams in this project?: Great communication. & coordination.

Did you feel the owner/architect had realistic expectations of the building's energy performance?: Yes. Owners are delighted on what has been achieved.

Have you received any negative feedback from the occupants, especially related to unique features of this building? What were they? Could the complaints/problems be resolved?: Don't recall any.

Have you received any positive feedback from the occupants, especially related to unique features of this building? What were they?: Lots. People like to have control over their environment.

Did the building need any "fixes" to improve the performance, which were not part of the original design?: During the commissioning there were a few corrective measures. Primarily programming the BMS. Some equipment issues with the split systems (poor quality).

Do you feel you were too "conservative" in any of the features (ie over use of mechanical lighting, oversized HVAC system, etc.): Very aggressive going with natural ventilation.

Do you feel that you over estimated the buildings thermal performance and undersized any parts of the mechanical system as a result?: No. natural. vent components all oversized.

Were there any project delays that were a direct result of Green Building criteria?: No

How were the ceiling fan sizes determined?: Manufacturer's. Guidelines

Are fans occupant-controlled, mechanically controlled, or both?: Occupant. Controlled with local switching and BMS override.

Have there been any complaints from the occupants about the fans being either too "windy" or not effective enough in circulating air?: Have not heard about that

Do you think that this building contains a large amount of thermal mass, do you notice if it "moderates" the space temperature?: Yes

Have there been problems with the building being too cool in the mornings?: Have not heard about that.

How did you determine how much mass was required and what impact the mass had on HVAC sizing?: Seismic guys did that.

What materials were used for mass? What special issues did the existing structure pose for incorporating enough mass?: Was not involved in the decision

What special challenges did this renovation project present?: Going with Natural vent., but it was straight forward for their firm.

Were any of the building's original features used for an unusual purpose?: CanŐt think of anything other than basement being used for seismic isolation.

How difficult was it to incorporate "Green" features with the building's existing design to achieve a sense of harmony?: Definitely very easy.

Was there any conflict between preservationists and the design team on this project?: No not really. Maybe the architect

How does the building's maintenance requirements compare in the "before" and "after" states?: Easier now he suspects. Just the steam boiler vs HW boiler is easier to maintain.

Describe the natural ventilation scheme. How did you determine how much ventilation was available/required?: Firms experience and state codes.

How much control do the occupants have with the ventilation?: Operable windows + ???