(Background) (Site Visits & Objectives) (Strategies & Results) (Conclusion) (References).

Site Visits and Objectives

Figure 7: One of the authors measures the true orientation of the building using an azimuth protractor.

THE OBJECTIVES

The objectives in undertaking this study were:

• to evaluate the energy performance of a public building.
• to determine the effectiveness of complicated energy strategies.
• to understand the effect of solar radiation on internal load dominated buildings.

SITE VISITS AND SURVEY

Figure 8: A member of the investigation team measures roof reflectance using a pyronometer.

We visited the site on two occasions over the course of two months. The purpose of these visits was to gather as much first hand information as possible. This data was used to simulate the building's energy performance when it was input into Calpas3. Calpas 3 is a computer simulation program that calculates thermal performance based on hourly figures. The collected data was codified using site survey sheets developed by the professor of our energy simulation class. These sheets organize the process of data collection and assure the surveyor that the information is as complete as possible.

An important section of the site survey is the occupant use of the building. Estimations of average daily public usage were made using the log books maintained by the Library's security staff. These logs give an indication of the number of people entering the building within a given hour. We estimated that the average number of people a day is 2500; we also estimated that most people stay approximately two hours. The number of staff was estimated at 75. The library is open from 9am to 9pm Monday through Wednesday, 9am to 6pm Thursday to Saturday, and 1pm to 5pm Sunday. For the computer simulation we averaged this to 10 hours a day, 7 days a week.

Figure 9: First floor plan. Conditioned space is hatched. (127K JPEG)

The next stage of our survey involved investigating the quantity of electrical equipment. This we did by physically counting the lights we could access, and then extrapolating for those we couldn't. We also took numbers of computers, photocopiers, computer printers, and other assorted equipment. We were also taken on a tour of the building mechanical equipment and control systems.

As part of the site survey it was necessary to note the material, thickness, color, surface area, orientation and tilt of all surfaces, be they wall, roof or slab. Measurements were taken for solar transmittance of glazing and the absorption of other surface materials. Envelope data was categorized into: roof, exterior walls, slabs, both on grade and suspended, interior walls, doors and windows. All these categories were coded, and then labelled on the floor plans, so any particular element can be easily identified. In the case of this project we were fortunate enough to be able to access the construction drawings. This allowed us to gather additional data about the construction of the walls and roofs in particular.

Figure 10: Second floor plan. Conditioned space is hatched. (120K JPEG)

In gathering all the data necessary to successfully complete the site survey forms, it was necessary to use some simple instruments. We used an azimuth protractor to measure the true orientation of the building. This instrument utilizes a site specific sun path diagram, that is then oriented to show due south, an angle is then taken to the building surface being measured and a rotation off true South can then be ascertained. This project is oriented due South. Another instrument that was used is the Lamda Hemisphere Pyronometer. This was used to measure shortwave reflectance of roofs, walls and surrounding ground surfaces. The transmissivity of glass was also measured for the South window. An 'Angle Finder' was employed to gauge the tilt of the roofs. A digital thermometer was used to check the buildings thermostat readings. Due to the sophisticated computer control of the buildings internal systems, thermostat settings can be manipulated from a central location. This results in accurate settings, and constant monitoring. Other tools used included cameras to facilitate documentation for reference and archival purposes. In order to calculate volumetric data for the building, we consulted the as-built drawings we had been given.

Figure 11: Fifth floor plan. Conditioned space is hatched. (115K JPEG)

Calpas3 was the computer simulation program we used to model the thermal properties of this building. This program models the heating and cooling loads of the building, using hourly thermal calculations. We were then able to compare the results with the actual energy consumption of the building, as presented in data given to us by the Library. Upon validating the simulation, the effects of different energy features could be studied, with a good degree of accuracy.

BASE CASE ASSUMPTIONS

• Floor area includes all five floors, excluding unconditioned spaces (fire escapes, HVAC system rooms, and unfinished, unoccupied areas on first floor).
• Volume includes the total volume of the first four floors, and the lower ft. of the fifth floor. (Air conditioning is designed to only service the lower 9 ft.)
• Infiltration was set high, due to the high number of people constantly coming through the entrance doors, that are not airlocked.
• The calculation of Internal Gain:
  • Lights = 4151.
  • People = 3675.
  • Equipment = 600.
  • TOTAL = 8426. kW/day.
• Thermostat settings are computer controlled at 75 deg F all year, according to the site survey.

Figure 12: Cross section. Conditioned space is hatched. (81K JPEG)


Figure 13: Longitudinal section. Conditioned space is hatched. (53K JPEG)

NOTE: All drawings on this page are Copyright 1992 Bruder DWL Architects.

Comments to author: vitalsigns@
ced.berkeley.edu

All contents copyright (C) 1998. Vital Signs Project. All rights reserved.

Created: 03/19/96
Revised: 09/09/02

http://www-archfp.ced.berkeley.edu/vitalsigns/workup/phoenix_lib/phoenix_visits.html