Project Monitoring

In order to fully understand the complex heat transfer processes that are taking place, knowledge of temperature variations through and across the roof system and in the house is an essential component of the research .

Temperature sensors

The most common sensors used to monitor performance were temperature sensors. Many of these sensors were embedded into the tray-mounted cells and positioned carefully, as the trays were being built in the workshop, before going to site.  This allowed pre-calibrated sensor placement to be quality controlled to a level that would not have been possible on site. mon1

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The diagrammatic representation shows the positioning of temperature and other sensors. There were two classifications of temperature sensored tray. These were Lightly Instrumented Panels (LIPs) and Heavily Instrumented Panels (HIPs). An LIP had just 2 sensors on the filter either side of the central cell. These were  also included in the HIPs, to check consistency of response , along with a multitude of other sensors and sensor types, as shown in the above animated diagram and detailed in the next section .

Other tray-mounted sensors

In addition to the temperature sensors the HIPs also incorporated 5 humidity sensors each, to chart the humidity level of air from entry through the Energyflo™ cells and when it comes through to the other side.
Differential pressure transducers were also fitted. The purpose of these devices was to measure the pressure drop across the Energyflo™ cells and therefore the resistance to air flow over time .

The final type of sensor installed was an air flow measurement device, a hot-film anemometer. Several of these anemometers were installed to allow air flows to be monitored in several of the LIPs and HIPs and in the supply and extract ducts at attic level. This allowed the inner cavity in the trays to monitored, to evaluate the impact of environmental interactions on airflow.

Attic sensors

Temperature and humidity sensors were also placed within the attic. On the one hand, some of the sensors enabled conditions in the warm attic to be monitored .  The attic floor insulation was removed to allow heat from the house to flow into the roof space.   However , as it is not a heated or controlled section of the house, attic temperatures have a greater likelihood of fluctuation when compared to other parts of the house. This, along with outdoor temperature variations, is what determines the performance of the dynamic roof system.

The other area of measurement was within the supply and extract ducting located in attic . This enabled both the air going into and the air leaving the house to be monitored . Three senso s types were used, temperature humidity and flow anemometers, enabling  the temperature volume and humidity of the air supplying and leaving the house to be monitored. This also allowed the heat exchanger performance to be tracked and provided data on average house conditions that could not be monitored otherwise.

Local weather station

A weather station was attached to the apex of the CALA Hazeldean house to provide local weather data. This station provides continuous readings for temperature, humidity and pressure close to the boundary of the house. In addition, it also provides rainfall, wind speed and wind direction measurements, offering the possibility of increasing our knowledge and understanding of system performance and how it reacts to different environmental conditions. The main benefits of having a local weather station is the availability of accurate weather data sampled at the same frequency and time as the other data that is being collected from the house.


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Sponsors The University of Aberdeen EBP Cala Carbon Trust