Experimental Study of Using Micro-Encapsulated Phase-Change Material Integrated into Hemp Shive Wallboard

Abstract

Phase change materials (PCMs) are now widely known as potential additives for building insulation materials to provide a thermal mass effect that helps conserve energy and maintain a comfortable indoor temperature. Therefore, the study presented in this paper focuses on an experimental investigation of the specific heat capacity and thermal conductivity of hemp shive mixed with PCMs. Industrially manufactured organic PCM-S50 received from MikroCaps Ltd. (Slovenia) has been used to further enhance respective properties of the product samples. The experimental boards were made from hemp shive by directly mixing 5% encapsulate PCMs into the mass. Cold pressing was used to manufacture the boards with Kleiberit urea formaldehyde resin glue as a binding agent. The experimental boards were made as 25 mm thick single-layer parts with a density of 300 ± 20 kg/m3, which qualify them as low-density boards. By adding nanocapsules during the board manufacturing process, the heat capacity is increased by 62%. Based on the great potential of using latent heat, it becomes a possible solution for the development of new technologies related to the automatic regulation of an indoor microclimate.

Production of Particleboard Using Various Particle Size Hemp Shives as Filler

“…Binder volume in the produced boards in this study is 10%, matching amounts used in similar research [ 38 , 39 , 47 ]. The application of the binder is described in Section 2.3 .…”

“…Experimental mixtures were prepared according to a recipe and consisted of 85% base material (hemp shives), 10% binder, and 5% water), named HS-1, HS-2, and HS-12 in Table 1 (HS—hemp shives) [ 47 ]. Additional boards named HS-1A and HA-2A were produced with particle pre-treatment or additive application during particle mixing with binder, described in Section 2.1.3 and Section 2.3 , MHF (Milled hemp fiber-shive) boards were produced from leftovers after material processing, described in Section 2.3 .…”

“…It was chosen because of its physical and chemical properties (UF resins are known for their hardness, low flammability, good thermal properties, and absence of color), cost, and efficiency of use with cold press technology for board materials. This technology could be easily replicated from scientific research to manufacturing processes [ 47 ]. The technical data sheet of the binder states that drying time at 20 °C is 4 h and 30 min; at 60 °C it is only 6 min.…”

“…Hemp shives used as the main ingredient can produce materials with great insulation properties. In previous research, the thermal conductivity values are in the range from 0.064 W/(mK) to 0.074 W/(mK) for hemp shive boards with UF binders or wood fiberboards [ 47 , 48 ]. For hemp shive boards already on the market, the given reference values are in the range from 0.072 W/(mK) to 0.094 W/(mK) [ 49 , 50 ].…”

Review on the Integration of Phase Change Materials in Building Envelopes for Passive Latent Heat Storage

“…Renewable materials, such as natural fibers, are considered as promising carbon sequestration resources with beneficial effects on the planet's ecosystems, living environment and energy efficiency [57][58][59]. Kirilovs et al [60] investigated the specific heat capacity and thermal conductivity of a wallboard made from hemp shives mixed with a commercial organic PCM, S50 at 5 wt%. The addition of nano-capsules increased the heat capacity by 62% to 2.369 J g −1 K −1 .…”