Psychological and Physiological Thermal Effects of Biophilic Built Environment using Virtual Reality: A Pilot Study for Certified Green Building
Description
Datasets used in the manuscript titled “Psychological and Physiological Thermal Effects of Biophilic Built Environment using Virtual Reality: A Pilot Study for Certified Green Building”. This study conducted a controlled experiment testing the psychological and Physiological thermal effects from visual stimuli of indoor environments incorporating natural elements (biophilic design) in certified green offices. This study used a virtual reality (VR) image of a certified green office emphasizing biophilic design, while measuring the physical environmental parameters, the participants’ subjective thermal perceptions, and physiological parameters (heart rate: HR, heart rate variability: HRV, salivary alpha-amylase activity: sAA) in the neutral and high temperature greenhouses (NTG and HTG, respectively). Air temperature, air velocity, relative humidity, globe temperature, and outdoor temperature were measured and used for calculating other thermal environmental indices (SET*, operative temperature, mean radiant temperature). The thermal perceptions were measured with self-report questionnaires (thermal sensation: TS, hot-cold sensation: HC, warm-cool sensation: WC, humid sensation: HS, thermal comfort: TC) in the Likert scale and the visual analog scale (VAS). HR, HRV (RMSSD, nHF, LF/HF), sAA were used as the indices of autonomic nervous activity. A total of 47 participants were recruited first, then two participants were excluded due to recording equipment failure, which makes the final number of participants 45. Participants were divided into two groups such as the control group only viewing VR images of the non-biophilic office, and the treatment group viewing VR images including the image for a biophilic office. Each participant stayed in greenhouses for 4 times: (1) NTG aiming at SET* 24℃ first (NTG1), followed by (2) HTG aiming at SET* 30℃ (HTG1), followed by (3) NTG for the second time (NTG2), then (4) HTG for the second time (HTG2). The control group viewed the same non-biophilic VR image in all 4 greenhouse sessions. The treatment group viewed the same non-biophilic VR image in NTG1, HTG1, NTG2, then the biophilic VR image in HTG2. The subjective thermal evaluation in the high temperature condition indicated that participants’ group viewing a biophilic VR image felt significantly cooler and more comfortable than the control group. By using the hot-cold sensation evaluation values, we estimated that the psychological cooling effect of the biophilic VR image was equivalent to 1.66℃, saving HVAC cooling energy up to 18.9% among thermal climate zones ranging from Cold Humid to Very Hot Humid. In this study, however, the physiological parameters were not different between the control and treatment groups. This study demonstrated the potential benefits of practical biophilic design improving occupant’s thermal comfort levels and saving building energy.