Posttemperature Effects on Shaft Capacity of a Full-Scale Geothermal Energy Pile

Shallow geothermal heat exchangers integrated in structural pile foundations have the capability of being an efficient and costeffective solution to cater for the energy demand for heating and cooling of built structures. However, limited information is available on the effects of temperature on the geothermal energy pile load capacity. This paper discusses a field pile test aimed at assessing the impact of thermomechanical loads on the shaft capacity of a geothermal energy pile. The full-scale in situ geothermal energy pile equipped with ground loops for heating/cooling and multilevel Osterberg cells for static load testing was installed at Monash University, Melbourne, Australia in a sandy profile. Strain gauges, thermistors, and displacement transducers were also installed to study the behavior of the energy pile during the thermal and mechanical loading periods. It has been found that the pile shaft capacity increased after the pile was heated and returned to the initial capacity (i.e., initial conditions) when the pile was allowed to cool naturally. This indicated that no losses in pile shaft capacity were observed after heating and cooling cycles. A variance in average vertical thermal strains was observed along the upper section of the pile shaft at the end of the heating periods. These were almost fully recovered at the end of the cooling periods, indicating that they are of an elastic nature. Pile average circumferential strains were found to be relatively uniform at the end of the heating and cooling periods and did not change with depth. They, also, were fully recovered during the cooling period. It was also observed that the increase of temperature during the heating periods prompted the pile shaft to expand radially. Subsequently, as the pile cooled down, the pile shaft slowly contracted and returned closely to its original condition, suggesting a thermoelastic behavior

Harnessing on site renewable energy through pile foundations

Incorporation of heat exchangers into pile foundations is a relatively novel sustainable technology for the intermittent storage of energy in soils with a view of utilising it for space heating and cooling of buildings by means of suitable systems integrated into buildings. This innovative technology can provide not only substantial long-term cost savings in relation to conventional energy systems but also can make an important contribution to environmental protection by reducing fossil energy use and minimising the carbon footprint of built structures. This paper reports on an ongoing project on heat exchanger pile foundations taking place at Monash University. It discusses the basic concept of an energy pile and governing design parameters such as thermo-mechanical loading and soil thermal properties and presents the field test set up currently running

Harnessing on site renewable energy through pile foundations

Incorporation of heat exchangers into pile foundations is a relatively novel sustainable technology for the intermittent storage of energy in soils with a view of utilising it for space heating and cooling of buildings by means of suitable systems integrated into buildings. This innovative technology can provide not only substantial long-term cost savings in relation to conventional energy systems but also can make an important contribution to environmental protection by reducing fossil energy use and minimising the carbon footprint of built structures. This paper reports on an ongoing project on heat exchanger pile foundations taking place at Monash University. It discusses the basic concept of an energy pile and governing design parameters such as thermo-mechanical loading and soil thermal properties and presents the field test set up currently running

Field and Laboratory Investigation of a Heat Exchanger Pile

Incorporation of heat exchangers into pile foundations is a relatively novel sustainable technology for the intermittent storage of energy in soils. Energy can be utilised in this way for space heating and cooling of buildings by means of suitable systems integrated into buildings. This paper relates to an ongoing study on the impact of coupled thermo-mechanical loads on heat exchanger pile foundations. This study evaluates the performance of a laboratory scale energy pile under different vertical stress levels, temperature gradients and heat transfer modes and presents the full-scale in situ energy pile setup equipped with ground loops for heating/cooling and multi-level Osterberg cells for static load testing

Recruitment and baseline characteristics of young adults at risk of early-onset knee osteoarthritis after ACL reconstruction in the SUPER-Knee trial

Objectives:The study aims to (1) report the process of recruiting young adults into a secondary knee osteoarthritis prevention randomised controlled trial (RCT) after anterior cruciate ligament reconstruction (ACLR); (2) determine the number of individuals needed to be screened to include one participant (NNS) and (3) report baseline characteristics of randomised participants. Methods:The SUpervised exercise-therapy and Patient Education Rehabilitation (SUPER)-Knee RCT compares SUPER and minimal intervention for young adults (aged 18-40 years) with ongoing symptoms (ie, mean score of &lt;80/100 from four Knee injury and Osteoarthritis Outcome Score subscales (KOOS4)) 9-36 months post-ACLR. The NNS was calculated as the number of prospective participants screened to enrol one person. At baseline, participants provided medical history, completed questionnaires (demographic, injury/surgery, rehabilitation characteristics) and underwent physical examination. Results:1044 individuals were screened to identify 567 eligible people, from which 184 participants (63% male) enrolled. The sample of enrolled participants was multicultural (29% born outside Australia; 2% Indigenous Australians). The NNS was 5.7. For randomised participants, mean±SD age was 30±6 years. The mean body mass index was 27.3±5.2 kg/m2, with overweight (43%) and obesity (21%) common. Participants were, on average, 2.3 years post-ACLR. Over half completed &lt;8 months of postoperative rehabilitation, with 56% having concurrent injury/surgery to meniscus and/or cartilage. The most affected KOOS (0=worst, 100=best) subscale was quality of life (mean 43.7±19.1). Conclusion:Young adults post-ACLR were willing to participate in a secondary osteoarthritis prevention trial. Sample size calculations should be multiplied by at least 5.7 to provide an estimate of the NNS. The SUPER-Knee cohort is ideally positioned to monitor and intervene in the early development and trajectory of osteoarthritis.</p