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I-Hub Product Testing Evaluation Report: Hivve Sustainable Modular Classrooms: Envelope and Heating Tests

Report


Type Of Work


  • Report

Abstract


  • The control of internal conditions within school classrooms is an important issue, with much focus on achieving appropriate temperatures for effective learning, and more recently, ensuring sufficient fresh air for learning and COVID risk minimisation. Providing these internal conditions through heating, ventilation and air-conditioning requires substantial energy, and has significant environmental implications.

    Transportable classrooms are a common feature of schools across Australia. These classrooms can be moved from schools to school to assist in dealing with fluctuating demographics. The buildings are typically lightweight construction with basic thermal envelope specification to meet the minimum standards at the time of construction. Historically, they were designed with operable windows, shading and electric wall heaters to provide thermal comfort, however new transportables are equipped with multiple split system AC for heating and cooling, and major projects are underway to retrofit split-systems to existing buildings.

    Hivve offers a transportable classroom package with many additional features designed to improve the thermal comfort and sustainability of these buildings. Features of a Hivve transportable include:

    •Higher performance thermal envelope relative to minimum standards, notably including double glazing;

    •An energy efficient split system Air-conditioning unit;

    •Rooftop PV generation, with the option of integrated battery storage;

    •A monitoring and controls systems to manage energy use and indoor environment.

    A number of Hivve transportables have been installed in schools around Australia, including two at Majura Public School in the ACT. The current technology evaluation report presents the results of an as-built performance evaluation of the thermal envelope and HVAC system of the Hivve transportables located at Majura, in comparison with the transportables buildings located at the i-Hub living laboratory sites, namely Amaroo and Fadden schools. The comparison of transportables included an older building with a very modern efficient AC unit at Fadden, and two more recently constructed transportables at Amaroo that appear identical yet have remarkably different energy performance; one has an efficient AC and good thermal envelope, while the other is around five years older and has a poorer thermal envelope and a less efficient AC unit.

    A series of tests were undertaken, designed to test firstly the building thermal envelope and heating system in combination, and then to test the performance of the building envelope with no active heating or cooling. The tests were undertaken during a COVID induced lock-down, in which there was no occupancy in the buildings. This allowed direct comparison that would not otherwise have been possible, as the usage and occupancy profiles of each transportable are substantially different.

    The active heating test included setting the air-conditioning system in each transportable to heat to a set-point of 25 °C and identified several items of interest. Firstly, of the three standard transportables (i.e. not Hivve transportables), two had issues with one of their twin AC units which meant they could not achieve the set point temperature. In one case (Fadden), one unit would regularly trip due to a faulty control board on the outdoor unit (diagnosed during the evaluation period). In the other case (Amaroo B13) the unit was not achieving the set point temperature, but using substantial energy. As a result of these issues, a valid comparison was only able to be made with Amaroo B14, which was a more modern building, with wall, ceiling and under-floor insulation and a high-efficiency Air-conditioning unit with a COP comparable to the Hivve units. Over the course of the 9 day testing period of continuous heating in September, the Hivve transportables used 13% and 2% less energy to maintain 25 °C when normalised by floor area, and 15% and 5% when normalised by heated volume.

    The free running test returned a valid comparison for all the transportable buildings, as there was no reliance on active heating. After a period of normalisation, all external doors and windows were closed and the blinds shut, and the internal conditions monitored for a period of 10 days. The test was conducted in late September to early October, and external conditions were clearly still within the heating season. The results confirmed the impact of the improved thermal envelope for the Hivve buildings, with both Hivve transportables showing higher mean, minimum and maximum temperatures during this period when outside temperatures in Canberra were low. The Hivve transportables also showed a lower diurnal temperature variation.

    This technology evaluation has evaluated the in-situ performance of the thermal envelope and HVAC system installed at Majura public school, in comparison to typical transportable buildings installed within the Fadden and Amaroo living laboratory. Notably, key features of the Hivve offering, namely the renewable energy system and Hivve IQ monitoring and controls systems, were not evaluated in this test, although a brief summary of their performance during the test period is included. A proposed future evaluation will explore in detail these renewable energy systems, and the performance of the building during occupied periods.

Publication Date


  • 2021

Citation


  • Tibbs, M., Daly, D., Kokogiannakis, G., McDowell, C., Roth, J., & Cooper, P. (2021). I-Hub Product Testing Evaluation Report: Hivve Sustainable Modular Classrooms: Envelope and Heating Tests. Wollongong, NSW, Australia: AIRAH. Retrieved from https://www.airah.org.au/

Web Of Science Accession Number


Place Of Publication


  • Wollongong, NSW, Australia

Type Of Work


  • Report

Abstract


  • The control of internal conditions within school classrooms is an important issue, with much focus on achieving appropriate temperatures for effective learning, and more recently, ensuring sufficient fresh air for learning and COVID risk minimisation. Providing these internal conditions through heating, ventilation and air-conditioning requires substantial energy, and has significant environmental implications.

    Transportable classrooms are a common feature of schools across Australia. These classrooms can be moved from schools to school to assist in dealing with fluctuating demographics. The buildings are typically lightweight construction with basic thermal envelope specification to meet the minimum standards at the time of construction. Historically, they were designed with operable windows, shading and electric wall heaters to provide thermal comfort, however new transportables are equipped with multiple split system AC for heating and cooling, and major projects are underway to retrofit split-systems to existing buildings.

    Hivve offers a transportable classroom package with many additional features designed to improve the thermal comfort and sustainability of these buildings. Features of a Hivve transportable include:

    •Higher performance thermal envelope relative to minimum standards, notably including double glazing;

    •An energy efficient split system Air-conditioning unit;

    •Rooftop PV generation, with the option of integrated battery storage;

    •A monitoring and controls systems to manage energy use and indoor environment.

    A number of Hivve transportables have been installed in schools around Australia, including two at Majura Public School in the ACT. The current technology evaluation report presents the results of an as-built performance evaluation of the thermal envelope and HVAC system of the Hivve transportables located at Majura, in comparison with the transportables buildings located at the i-Hub living laboratory sites, namely Amaroo and Fadden schools. The comparison of transportables included an older building with a very modern efficient AC unit at Fadden, and two more recently constructed transportables at Amaroo that appear identical yet have remarkably different energy performance; one has an efficient AC and good thermal envelope, while the other is around five years older and has a poorer thermal envelope and a less efficient AC unit.

    A series of tests were undertaken, designed to test firstly the building thermal envelope and heating system in combination, and then to test the performance of the building envelope with no active heating or cooling. The tests were undertaken during a COVID induced lock-down, in which there was no occupancy in the buildings. This allowed direct comparison that would not otherwise have been possible, as the usage and occupancy profiles of each transportable are substantially different.

    The active heating test included setting the air-conditioning system in each transportable to heat to a set-point of 25 °C and identified several items of interest. Firstly, of the three standard transportables (i.e. not Hivve transportables), two had issues with one of their twin AC units which meant they could not achieve the set point temperature. In one case (Fadden), one unit would regularly trip due to a faulty control board on the outdoor unit (diagnosed during the evaluation period). In the other case (Amaroo B13) the unit was not achieving the set point temperature, but using substantial energy. As a result of these issues, a valid comparison was only able to be made with Amaroo B14, which was a more modern building, with wall, ceiling and under-floor insulation and a high-efficiency Air-conditioning unit with a COP comparable to the Hivve units. Over the course of the 9 day testing period of continuous heating in September, the Hivve transportables used 13% and 2% less energy to maintain 25 °C when normalised by floor area, and 15% and 5% when normalised by heated volume.

    The free running test returned a valid comparison for all the transportable buildings, as there was no reliance on active heating. After a period of normalisation, all external doors and windows were closed and the blinds shut, and the internal conditions monitored for a period of 10 days. The test was conducted in late September to early October, and external conditions were clearly still within the heating season. The results confirmed the impact of the improved thermal envelope for the Hivve buildings, with both Hivve transportables showing higher mean, minimum and maximum temperatures during this period when outside temperatures in Canberra were low. The Hivve transportables also showed a lower diurnal temperature variation.

    This technology evaluation has evaluated the in-situ performance of the thermal envelope and HVAC system installed at Majura public school, in comparison to typical transportable buildings installed within the Fadden and Amaroo living laboratory. Notably, key features of the Hivve offering, namely the renewable energy system and Hivve IQ monitoring and controls systems, were not evaluated in this test, although a brief summary of their performance during the test period is included. A proposed future evaluation will explore in detail these renewable energy systems, and the performance of the building during occupied periods.

Publication Date


  • 2021

Citation


  • Tibbs, M., Daly, D., Kokogiannakis, G., McDowell, C., Roth, J., & Cooper, P. (2021). I-Hub Product Testing Evaluation Report: Hivve Sustainable Modular Classrooms: Envelope and Heating Tests. Wollongong, NSW, Australia: AIRAH. Retrieved from https://www.airah.org.au/

Web Of Science Accession Number


Place Of Publication


  • Wollongong, NSW, Australia