Dynamic simulation and full-scale testing of a pre-fabricated straw-bale house

Abstract

Straw is an agricultural by-product and, after accounting for use in animal bedding, the mushroom sector, and Biomass power stations, there is an annual overall net straw surplus in Great Britain of approximately 5.5 million tonnes. The use of this non-food crop in construction is considered beneficial not least for the sequestration of carbon during production. The availability and inherent sustainability of this building material has led to a resurgence in its use over the last decade. As many countries strive towards low or zero carbon targets for building energy use, designers are exploring new methods of construction using natural materials such as straw, which, due to its insulating properties, has the potential to significantly reduce the energy required for space heating. However, there is a lack of scientific research into the thermal performance of straw-bale buildings, particularly in the UK. This paper presents the results of computer simulations and initial field-testing of the thermal performance of a BaleHaus constructed using ModCell pre-fabricated modular panels. A highly-instrumented two-storey BaleHaus has been built on the University of Bath (UK) campus. For this study, the internal environment was monitored by wireless Relative Humidity and Temperature (RHT) sensors at 12 locations whilst a weather station close to the building records the external environmental conditions.The results of co-heating and air-tightness tests are presented in addition to dynamic simulation modelling which predicts the annual energy use and CO2 emissions.