Temperature Monitoring Data

Comparison of outdoors, cabin, greenhouse & sunroom for 1-14-2002

In this graph of the logged temperature conditions, several pieces of information can be gleaned about the behavior of the thermal behavior of these spaces that receive no supplemental heat beyond what is provided by the sun.

In the early morning hours, midnight to 8 a.m., the differences between the spaces and the outdoors reflects the effectiveness of the space to store heat overnight. The least effective is the greenhouse, with its huge expanse of single glazed glass. Next is the cabin, with less glazing, and finally the sunroom with both less glazing and more thermal mass than the cabin.

Once the sun comes out, the cabin is the first to reflect this fact, especially since it has a very good morning exposure to the sun. As the day progresses, however, the cabin becomes shaded and this is reflected in the decrease in its temperature.

By 10:30 a.m., with the greenhouse receiving a good dose of sunlight, its temperature reaches 60ºF and slowly builds through the day even though some of the solar-derived heat is being stored in the 11 tons of rock storage. The result is that the greenhouse remains very comfortable through the day without overheating. Despite the active rock storage, the large expanse of single glazing offers little resistance to the loss of this heat once the sun goes down. Although by midnight of this sunny day the greenhouse is still 9ºF warmer than outdoors in comparison to the fact that it began the day at only 4ºF warmer than the outdoors.

The temperature rise in the sunroom, which began at 9:00 a.m. ceases at around 11:30 a.m. when the fan transfer system kicks in and starts to warm the shop.

Future monitoring efforts will examine the relationship between the rock storage and the soil bed in the greenhouse as well as between the sunroom and the shop.