The Vital Signs Project: The Gund-Ream Ranch Case Study

Our Investigation






Our study of the Gund-Ream Ranch House followed the format below.

  1. Developing some strategies as a group prior to our first site visit.
  2. First site visit which included introductions and visual documentation..
  3. Contacting owners and requesting further information such as construction drawings and energy bills.
  4. Discussion as a group our initial findings.
  5. Second site visit consisting of hobo collection and further visual documentation.
  6. Formulating hypotheses based on the documentation collected and current progress. Analyzing our data and writing up this report.


This page describes parts 1-5 of our investigation. The hypotheses and analysis sections are presented on the following pages.



Developing Strategies

Three weeks prior to visiting the Gund-Ream Ranch, we were intorduced to the Vital Signs Project and asked to decide on a building to analyze. We were intrigued with the incorporation of the earth sheltering design strategy used in the Gund-Ream Ranch House. We also enjoyed the use of passive solar design collecting southern and eastern light and heat. Earth sheltering is a strategy that is seldom utilized due to the complexity of the structural systems (weight considerations) and difficulties in waterproffing. Yet this type of design does possess some distinct advantages, mainly providing thermal insulation and is naturally environmentally sound. Our group then developed and focused on these general questions;

 

 

Our location in relationship to this house, as well as a limited time schedule forced us to keep our investigations simple and manageable. It also is in keeping with the Vital Signs emphasis on quick studies focusing on one or two issues, rather than definitive, all-encompassing building investigations. Our qualitative data was collected through photographs and analysis of the construction drawings. Our quantitative data was collected using Hobo Temperature Loggers as well as acquiring energy bills over a one year period from the owners.

The energy bills that we recieved from the owners revealed some interesting data in that the largest energy consumer of the Ranch's many buildings turned out to be the Gund-Ream Ranch House. As the chart illustrates, both gas and electrical consumption follows yearly trends of winter cold and summer heat. But note that the major consumer is the natural gas. The main heat source for the house is the radiant floor heating system which operates on natural gas. Keeping the residence at a constant temperature of 65 degrees farenheit throughout the year explains this trend. Electricity usage is based on occupancy such as traditional appliances and lighting.

 

 

 

 


HOBO Temperature Loggers were used to collect constant temperature readings every 9 minutes over a ten day period.

Location

#1 Interior floor in main room

#2 Interior top plate

#3 Exterior top plate on northwest side

#4 Exterior skylight

#5 Interior skylight

 

HOBO placement in the Gund-Ream Ranch House



In order to keep our data collection and analysis simple, we focused on using our quantitative temperature measurements to reveal basic building performance over a period of time. The HOBO's were provided by our Vital Signs course at the University of Idaho. Though we did not have specific hypotheses to guide us as we placed the sensors, we tried to arrange them to give us a broad range of data for use in testing our hypotheses. We decided to narrow our data down to one 24 hour day with varying temperatures.


#4 vs #5

Exterior skylight= blue

Interior skylight= red

The temperature of the interior skylight remains consistant with the fluxuations in the radiant floor heating system. According to our chart the heat from the radiant floor heating system reaches the ceiling at approximately 0:02. The chart also illustrates that the heat slowly radiates through the skylight to the exterior over a peroid of approximately eight hours (7:14-16:02). Thus an eight hour cycle of heat loss is revealed.

 

 

#1 vs #2

Interior floor = blue

Interior top plate = red

Data in this chart reveals a large initial heat distribution of the radiant floor at approximately 1:45 a.m. As the day progresses the heating fluxuations remain but at much smaller intervals. The interior top plate illustrates a gradual warming trend followed by a cooling trend. Yet the variance is minimal staying within a 64-70 degree range. A result such as this is interesting in that this particular connection has a tendency to be traditionally a cold connection in many homes. This tells us that the wall to roof connection works well in its ability to retain heat.

 


#1 vs #5

Interior floor = blue

Interior skylight = red

According to our data the interior skylight does actually function as a chimney. The floor reaches a heating peak at approximately 1:36 a.m. and reaches the skylight at approximately 7:14 a.m. reaching a peak temperature of approximately 73 degrees farenheit at about 16:50 p.m. The ceiling along with the skylight create an avenue for warm air resulting in a "chimney effect". In this case the heat from the radiant floor rises up along the ceiling and out through the skylight to the exterior.

#2 vs #5

Inside top plate = blue

Interior skylight = red

The preivous chart illustrates the origin of the heat. This chart illustrates the result at the top of the walls in relation to the skylight. A significant difference in temperature is revealed illustrating a "chimney effect". As indicated the temperature difference remains consistant throughout this 24 hour time frame with the most extreme difference of about 8 degrees occuring at approximately 17:00.

#3 vs #4

Exterior skylight = red

Outside top plate = blue

This chart reveals the heat loss through the skylight directly. The outside top plate indicates a fluxuation of approximately 32-57 degrees farenheit. but the exterior skylight indicates a fluxuation of approximately 42-52 degrees farenheit. Both HOBO's were placed outside the building in the northwestern exposures. The skylight, since it is located at a higher extremity, should have indicated cooler temperatures. But as the chart illustrates the exterior skylight reaches temperatures almost 10 degrees warmer than the exterior top plate. This occurance is inteesting in that it illustrates the heat loss through the skylight during the cooler periods in the day.


#2 vs #3

Inside top plate = blue

Outside top plate = red

Our final chart shows the thermal efficiency of the wall. As illustrated the inside top plate temperature remains within a range of approximately 64-68 degrees compared to the outside fluxuations of approximately 32-56 degrees. This is due, in part, to the rolling contours of the exterior earth sheltering diverting and/or blocking the wind from entering the building. This information also illustrates good thermal connections at the clerestory windows and at the roof wall connection.





Comments to author: mose9231@uidaho.edu, wong9195@uidaho.edu