Examination and optimization of the design parameters for the thermal hysteresis phenomenon of the phase change material

Phase change material (PCM)-enhanced building envelopes can control indoor temperatures and save energy. However, PCM needs to undergo a phase change transition from solid to liquid and back to be fully effective. Furthermore, most previous research integrated PCM with high embodied energy materials. This study aims to advance the existing research on integrating PCM into carbon-negative wall assemblies composed of hempcrete and applying temperature control strategies to improve wall systems’ performance while considering the hysteresis phenomenon. Four hempcrete and hempcrete-PCM (HPCM) wall design configurations were simulated and compared under different control strategies designed to reduce energy demand while enhancing the phase change transition of the microencapsulated PCM. The HPCM wall types outperformed the hempcrete wall assembly through heating (~3–7%) and cooling (~7.8–20.7%) energy savings. HPCM walls also maintained higher wall surface temperatures during the coldest days, lower during the warmest days, and within a tighter range than hempcrete assembly, thus improving the thermal comfort. However, the results also show that the optimal performance of thermal energy storage materials requires temperature controls that facilitate their charge and discharge. Hence, applied control strategies reduced heating and cooling energy demand in the range of ~4.4–21.5% and ~14.5–55%, respectively.

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Effect of design parameters on thermal performance of integrated phase change material blind system for double skin façade buildings

International Journal of Low-Carbon Technologies ◽

10.1093/ijlct/ctz010 ◽

2019 ◽

Vol 14 (2) ◽

pp. 286-293

Author(s):

Yilin Li ◽

Jo Darkwa ◽

Georgios Kokogiannakis ◽

Weiguang Su

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Thermal Performance ◽

Design Parameters ◽

Double Skin ◽

Change Material

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PVT Cell Performance Characteristics and Efficiency with Phase Change Material

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.e1053.069520 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1005-1012

Keyword(s):

Phase Change ◽

Phase Change Material ◽

Storage Capacity ◽

Design Parameters ◽

Back Side ◽

Photoelectric Conversion ◽

Electrical Efficiency ◽

Pv Panel ◽

Fin Design ◽

Change Material

The PV panel temperature increase causes the drop in output power and electrical efficiency . The power generation of PV module is highly influenced by the temperature and so cooling is required to increase the PV panel electrical efficiency. PV panel electrical efficiency can be increased by keeping the low operating temperature as low as possible, preferably at temperature of 250 C and irradiation 1000 w/m2 . The temperature regulation with efficient control methods of PV modules can increase its efficiency by a significant level. The PVT-PCM systems elevated about 28 to 42% more heat storage capacity than that of for a longer period and around 8 to 12 % escalation in output. The application of phase change materials (PCM) can be a better solution for this purpose, because phase change material (PCM) has large energy storage capacity and nearly constant charging / discharging temperature during phase change transitions .It can be used to regulate the PV cell temperature and store the thermal energy for solar heating systems photoelectric conversion efficiency of a PV system was improved by using different PCM. In this study we are trying to increase the efficiency by using different fin layout of the heat sink and comparing the experimental data for optimal fin design to effectively disperse heat through PCM material. The PVT panel surface back side was attached with the aluminum container with different (Geometric, Spherical & fins) configurations with PCM and with out PCM of single/different materials. Present study carried on aluminum H-30 box holding PCM material with fins and covering plate to which the photo voltaic cell attached then a different sensors to collect temperature data and irradiation levels at different regions. The design parameters was changed with fins and geometrical shape and found the derating factor. The derating factor was found with fins and with out pins along with PCM and with out PCM. Both experimental and theoretical values were compared ,the study revealed that the derating factor value was 13.2 without PCM the and 4.40 with PCM with out fins . The results revealed that relation between experimental measurement values and theoretical values . The study confirmed PCM with better fin design will increase the effective surface area can increase the cooling of PVT panel , results the escalation in electrical out put

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Thermodynamics of Energy Storage by Melting Due to Conduction or Natural Convection

Journal of Solar Energy Engineering ◽

10.1115/1.2929642 ◽

1990 ◽

Vol 112 (2) ◽

pp. 110-116 ◽

Cited By ~ 33

Author(s):

M. De Lucia ◽

A. Bejan

Keyword(s):

Energy Source ◽

Natural Convection ◽

Energy Storage ◽

Phase Change ◽

Phase Change Material ◽

Melting Process ◽

Absolute Temperature ◽

Design Parameters ◽

Environment Temperature ◽

Change Material

This paper describes the most basic thermodynamic aspects of the process of energy storage by melting of a phase change material when the energy source is a stream of hot single-phase fluid. The first part of the paper considers the melting process ruled by pure conduction across the liquid phase, and the second part deals with the quasi-steady melting dominated by natural convection. The paper establishes the relationship between the total irreversibility of the melting process and design parameters such as the number of heat transfer units of the heat exchanger placed between the energy source and the phase change material, the duration of the melting process, and the position of the energy storage process on the absolute temperature scale. It is shown that the exergy transfer to the melting material is maximized when the melting temperature (Tm) equals the geometric average of the environment temperature (Te) and the temperature of the energy source (T∞), in other words when Tm=(TeT∞)1/2. This conclusion holds for both conduction-dominated melting and convection-dominated melting.

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Phase Change Material Melting in an Energy Storage Module for a Micro Environmental Control System

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4040896 ◽

2018 ◽

Vol 10 (6) ◽

Cited By ~ 1

Author(s):

Mustafa Koz ◽

H. Ezzat Khalifa

Keyword(s):

Control System ◽

Energy Consumption ◽

Thermal Comfort ◽

Phase Change ◽

Phase Change Material ◽

Environmental Control ◽

Design Parameters ◽

Airflow Rate ◽

Local Cooling ◽

Change Material

Abstract An experimentally validated finite element model (FEM) was developed to analyze the design parameters of a latent heat storage device (LHSD) for a micro environmental control system (μX). The μX provides local cooling to an office worker in a room whose thermostat setpoint has been elevated from 23.9 °C (75 °F) to 26.1 °C (79 °F) in order to reduce heating, ventilation, and air conditioning (HVAC) energy consumption. For this application, the LHSD is designed to provide ≥50 W of cooling for a full, 8.5 h workday to restore thermal comfort in the warm, 26.1 °C room. The LHSD comprises several parallel slabs of encased phase change material (PCM) with interposed airflow channels. The airflow rate is selected to obtain ≥50 W of cooling at the end of the 8.5 h operation. The LHSD exhibits a decreasing cooling rate over the 8.5 h period when a constant airflow is passed through it, indicating that more cooling is supplied during the day than the minimum 50 W required for thermal comfort. The parametric analysis explores the effects of PCM thermal conductivity, slab thickness, air channel width, and number of slabs on LHSD performance. Parametric cases are compared against each other on the basis of their required PCM mass and energy consumption.

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