Thermal Analysis Report

ARCH 533: ADVANCED ENVIRONMENTAL SYSTEMS

Thermal Analysis:

Kindergarten and Community Center Lima, Peru

David Witte June 5, 2017

0. Project Information: Community Center and Kindergarten redesign

PERÚ

Conditions of extreme poverty

Municipality of Lima

ZAPALLAL

Coordinates: 11°49’09.0”S 77°05’45.1”W

ECT LOCATION

Perú Population_30 million Facing the rapid disappearance of glacial water supplies and decreased agricultural productivityOF LOMAS DE SETTLEMENT Annual slum growth rate_3.4%

0. Project Information: Community Center and Kindergarten redesign Current building use: Inside is a kindergarten and community gathering place. The exterior patio to the north is covered with shade cloth to provide a more comfortable meeting space outside, but it blocks solar exposure to the northern windows, making the inside rather dark.

1. Weather Information - Climate Consultant Dry Bulb temperatures

Summer - Dry Heat

Winter - Cold Fog

1. Weather Information - Climate Consultant Sun Shading Chart

Summer

Winter

1. Weather Information - Climate Consultant Psychometric Chart

1. Weather Information - Climate Consultant Solar Radiation

Imperial

Metric

1. Weather Information - Climate Consultant Wind Rose - Speed and Direction

2. Insulation Analysis - DIVA

Horizontal Roof 560.8 KWh/M2 556.46 KWh/M2 423.44 KWh/M2 655.69 KWh/M2 1553.8 KWh/M2

NORTH EAST SOUTH WEST ROOF Normal Surface Orientation

10.440 Sloped Roof 560.82 KWh/M2 555.34 KWh/M2 423.58 KWh/M2 653.99 KWh/M2 1556.09 KWh/M2 10.44 0 for Roof (Latitude x .87)

South

East

East

South

North

Roof

West

North

Roof

West

North

North

N

West

Roof

South

East

West

Roof

East

South

The maximum solar radiation for Lima, Peru is a surface tilted 10.4 degrees. Latitude x .87 is an equation for latitudes under 25 0. It accounts for the entire solar exposure of the day, not just noon. There is not a large difference because Lima is close to the equator.

3. Thermal Analysis The building being studied is used as a classroom. Below is the scenario of the existing building Facade height: 8’- 0” Facade Width: 50’- 0” Room Depth: 23’-0” Orientation: North Loads will be based off of table presented in class (below). The initial studies will not use natural ventilation.

3. Thermal Analysis I pulled the information below from various sources, in order to produce accurate data for Lima, Peru.

3. Thermal Analysis - Glazed Wall (3X8 Window Grid)

1) Single Pane Glazed Wall

2) Double Pane, Low E, Low Solar

3) Double Pane, Low E, Opaque

Fig 1: Annual Scenario Energy use The summary of the building performance (Fig 1.) shows that option 3 uses the least amount of energy. Fig 2 shows that there is a negligible difference in first cost. But as the following graphs will show, cost and energy performance are not the only factors that should be considered when choosing glazing options.

Fig 2: Total First Cost

Fig 3: Monthly Avg. Window Heat Gain Fig 3. Shows that why the cooling load is considerably less for the double pane opaque windows. Option 3 has very low amounts of monthly window heat gain because the opacity blocks the transmission of solar energy.

But energy use alone is not sufficient to make a selection, as the opaque windows will block any useful daylight illuminance.

Fig 4: Useful Daylight Illuminance Levels The chart above shows that while option 3 produces the lowest cooling loads for the building, it will result in insufficient daylight levels for most of the space. Option 1 and 2 have high lighting levels, but fall withing the useful range (after 2 meters of overlit space).

Fig 5: Thermal comfort As far as comfort is concerned, option 3 again performs the best, but the variance between the choices is minimal.

Window selection of Glazed Window Wall Considering the various performance criteria (thermal and visual comfort, initial cost, and overall energy performance) I would promote the use of option 2, double pane, low e, low solar. The main factor making this the best choice is the ability to utilize natural light, and allowing views to the surrounding environment.

3. Thermal Analysis - Proposed design of Kindergarden from Module 2 (clerestory added)

4) Single Pane Glazed Wall

7) Double Pane, Low E, Low Solar

8) Double Pane, Low E, Opaque

Fig 6: Annual Scenario Energy use The summary of the building performance in the proposed configuration (Fig 6.) shows that, again, double pane, low e, opaque windows use the least amount of energy to maintain comfort.

Fig 7 shows that there is a negligible difference in first cost. But as the following graphs will show, cost and energy performance are not the only factors that should be considered when choosing glazing options.

Fig 7: Total First Cost

Fig 8: Monthly Avg. Window Heat Gain Fig 8. Shows that why the cooling load is considerably less for the double pane opaque windows. Option 8 has very low amounts of monthly window heat gain because the opacity blocks the transmission of solar energy.

But energy use alone is not sufficient to make a selection, as the opaque windows will block any useful daylight illuminance.

But comparing this configuration to the previous scenario (Glazed Window Wall), the amount of heat gain is significantly less. The peak of option 4 comes just over 1.2 kBtu/ft2-yr while option 1 peaks at 4.5 kBtu/ft2-yr

Fig 9: Useful Daylight Illuminance Levels The chart above shows that while option 8 produces the lowest cooling loads for the building, it will result in insufficient daylight levels for most of the space. Option 1 and 2 have high lighting levels, but fall withing the useful range (after 2 meters of overlit space).

Fig 10: Thermal comfort As far as comfort is concerned, option 8 again performs the best, but the variance between the choices is minimal.

Window selection of Proposed Clerestory System Considering the various performance criteria (thermal and visual comfort, initial cost, and overall energy performance) I would promote the use of option 7, double pane, low e, low solar. The main factor making this the best choice is the ability to utilize natural light, and allowing views to the surrounding environment.

Facade design #2 has a lower window/wall ratio, allowing the space to have better thermal insulation from solar radiation. In addition to lower cooling bills, the first cost is also much lower ($17,000 vs. $36,000), and the comfort and useful daylight are relatively similar for both designs.

3. Thermal Analysis - Step 3 - Shading devices

7) Shading Mesh

8) Shallow Horizontal Shades 3’

9) Deep Horizontal Shade 10’

Fig 11: Annual Scenario Energy Use

The three shading options are as follows: 7) Exterior screen with a dark, fine mesh (1mm) 8) 3’-0” shades above the ground windows and clerestory window 9) No shade over clerestory, and 10’ shade over ground windows.

The exterior mesh screen has a high initial cost, without much energy savings compared to simple 3’ horizontal shading devices. Additionally, Figure 13. shows that the shading device results in lower heat gain on the window throughout the year.

Fig 12: Total First Cost

Fig 13: Monthly Avg. Window Heat Gain

Fig 14: Clerestory Window Heat Gain

Fig 15: Ground Level Window Heat Gain

Fig 16: Useful Daylight Illum. Levels - Spring Figures 14 and 15 were included because it shows the window heat gain of the clerestory compared to the ground windows, especially important in option 9, as there is no shade in the clerestory window, as this is designed to let daylight deep into the space, best seen in Figure 16, showing a balanced, useful light level up to 7 meters from the window ( the entire depth of the space). This results in a significantly lower initial first cost of lighting (Fig. 12).

Unfortunately, the additional exposure to solar radiation results in an increased cooling load, pushing the overall energy use to 35 kBtus /ft2-yr.

Conclusion The best performing building performance, with the lowest initial cost of windows is option 8. The lighting performance is almost within the useful range, allowing minimal electric lighting to make up the difference.

Overall, cooling loads are what drive the mechanical systems in Peru, with virtually no heating needed. For these reasons, blocking direct light is fairly important to maintaining an energy efficient building.

Appendix Sources for data input for Lima, Peru in Comfen

0.578 lbs CO2/kWh https://www.ashrae.org/File%20Library/docLib/Public/20081111_CZTables.pdf

https://en.wikipedia.org/wiki/Electricity_sector_in_Peru