Thermal Performance Evaluation of Coconut Coir Fiber Multi-Layer Insulation in Elevated Water Storage Tanks

Abstract

Elevated water storage tanks in tropical climates are susceptible to significant heat gain, leading to elevated water temperatures and reduced utility. This study experimentally evaluates a coconut coir Fiber-based multi-layer insulation system comprising an inner virgin plastic tank, coconut coir Fiber, polyurethane foam, and an outer protective plastic layer. Two identical 15-liter tanks—insulated and non-insulated—were monitored under ambient summer conditions with hourly temperature measurements. Results demonstrate that the insulated tank significantly mitigates peak temperature rise, enhancing thermal stability. The combination of coconut coir Fiber and polyurethane foam provides effective thermal resistance while maintaining cost-efficiency and sustainability. This system offers a practical, eco-friendly solution for controlling heat gain in elevated water storage tanks.

Introduction

This study addresses the problem of temperature fluctuations in elevated water storage tanks, which occur due to extreme weather conditions. In hot climates, solar radiation significantly increases water temperature, while in cold regions, low temperatures reduce usability and comfort. These variations increase dependence on energy-intensive heating and cooling systems.

To improve thermal stability, the research proposes a cost-effective and eco-friendly multi-layer insulation system using coconut coir fiber, polyurethane (PU) foam, and virgin plastic. Natural fibers like coconut coir are highlighted for their low thermal conductivity, sustainability, and biodegradability, making them suitable alternatives to conventional insulation materials such as fiberglass.

The study’s objectives include designing, fabricating, and evaluating the insulation system, comparing insulated and non-insulated tanks, analyzing the effect of thickness and material combinations, and assessing long-term sustainability.

An experimental setup was conducted using two identical 15-liter tanks:

• One non-insulated (control)

• One insulated with a multi-layer structure:

  • Inner virgin plastic (3 mm)

  • Coconut coir fiber (10 mm)

  • Polyurethane foam (25 mm)

  • Outer virgin plastic (7 mm)

Temperature was monitored for 24 hours using DHT11 sensors, with data transmitted via an ESP8266 Wi-Fi module to a cloud platform for real-time tracking.

Key Results

• Maximum temperature of non-insulated tank: 42°C

• Maximum temperature of insulated tank: 30°C

• Temperature reduction achieved: up to 12°C

• Heat transfer reduced from 16 W (non-insulated) to 3.66 W (insulated)

• Thermal resistance significantly increased in the insulated model

Conclusion

The study confirms that a multi-layer insulation system using banana fiber and polyurethane foam effectively reduces heat absorption in overhead water tanks. The insulated model showed a maximum temperature reduction of 14.4°C during peak hours and reduced heat transfer rate by approximately 78%. This eco-friendly and cost-effective solution can be implemented in residential water storage systems in tropical regions.

References

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Copyright

Copyright © 2026 Mani Shankar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.