Copyright © 2022 the Authors. This is an open-access article distributed under the creative commons attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited. 1. Introduction It is believed that there would be considerable difficulties with heat storage for the long-term and wide spread to use solar energy for domestic cooling and heating in all regions. The majority of storage devices on the market today use water as their main ingredient. The majority of systems require storage optimization to increase performance. This can be done by lowering the cost of storage or increasing storage density, which enables the storage and withdrawal of more energy from a given volume of storage (reduce losses, use other materials, use other designs). While passive methods don't require any direct external power, active methods need it [2]. PCM is thought of as passive heat transfer improvement technique, Murali et al. [3], Kiyaroudi [4] conducted an experimental investigation on the improvement of heat transport in SHTHEs. It has been found that rising the loop measurement, curl pitch, and mass stream rate in helical curl cylinders and shells can accelerate heat move. The cool water stream rate and loop not set in stone to be the most urgent factors utilizing the Taguchi technique. Interestingly, sun powered nuclear power can be put away as idle intensity by utilizing reasonable stage change materials, which can offer high accumulating limit per unit volume and per unit mass [2]. This is basically in light of the fact that most materials' inactive power of blend is far higher than their enthalpy changes (for example, the extent of idle force to the specific power of water is around 80). When phase change material (PCM) melts, more heat can be absorbed, which is sometimes more heat than necessary during the day. When the PCM returns from the liquid to the solid phase in the evening and at night, it can then release this heat into the surrounding medium. Such a technique for capacity is likewise useful in decreasing temperature changes in a sun oriented warm framework by engrossing the additional intensity during top radiation hours and it is absent to deliver it when sun-based radiation. Albeit unsaturated fats and paraffin wax have been utilized as warm stockpiling in sun powered warming and cooling applications, their essential downside is unfortunate warm conductivity. Along these lines, less intensity is held during dissolving and more is transmitted during hardening. In natural PCMs, for example, metal nanoparticles, nanofibers, or embedded metal framework, scientists commonly disperse nanoparticles with high intensity conductivity, Kiyaroudi [4]. Mettaweea and Assassa [5] performance of a compact phase change material (PCM) solar collector based on latent heat storage with experimental investigation. The charging process, the average heat transfer coefficient increases sharply with increasing the molten layer thickness, as the natural convection grows strong. The objective of the present paper is to enhance solar heating power by building an experimental station for heating solar water consisting of a flat plate solar collector (FPSC) filled with PCM for domestic purposes during the night and integrated with helical heat exchanger. Basrah Journal for Engineering Sciences, Vol. 22, No. 2, (2022), 72-79 Original Article Journal homepage: www.bjes.edu.iq ISSN (Online): 23118385, ISSN (Print): 18146120 An Experimental Study to Improve Solar Heating Water Using PCM and Integrated with Helical Heat Exchanger Fahad S. Fahad 1, *, Ibrahim Koc 2 1 Thermal Mechanical Engineering Basrah Technical Institute, Basrah, Iraq 2 Mechanical Engineering Department, Altinbas University, Mahmutbey, Dilmenler Cd. No:26, 34217 Bağcılar/İstanbul, Turkey E-mail addresses: fahadsadoun5@gmail.com , ibrahim.koc@altinbas.edu.tr Received: 22 July 2022; Accepted: 13 September 2022; Published: 24 December 2022 Abstract Solar energy can only be used when it's sunny outside. Therefore, solar heating is only efficient during the day and decreases at night or on overcast days. Consumer energy needs have a distinct seasonal structure, and solar energy cannot completely meet those needs. In order to satisfy customer demand, energy storage is essential. In order to maximize the use of solar energy and to increase the energy and efficiency of the solar absorption system, superior thermal properties of sophisticated materials, such as phase change materials, are important [1]. In the current study, 20 kg of phase change material (PCM) is integrated with solar water heating and fed into a storage tank to enhance the solar water heating efficiency. Helical coil heat exchangers were added to the storage tank as an external load. The trials were conducted in four separate months (September 2021, April, May, and June 2022) that were chosen on the first day. The effectiveness, heat gain, and significance of the phase change material in increasing heating efficiency throughout the day were studied using a range of variables, including water volume flow rate (2, 3, 4, 6, and 8 L/min) and inlet water temperature (25, 30, and 35 °C). The results showed that, given an initial temperature of 25 °C, the daily efficiency range, was 0.58 to 0.65, and that the daily final outlet temperature was enhanced outlet temperature over 65 °C. Additionally, on all test days, the heat released by the phase change material was audible in the evening and increased the utilization time. Keywords: Heat transfer, Solar energy, PCM, Heat exchanger. © 2022 The Authors. Published by the University of Basrah. Open-access article. https://doi.org/10.33971/bjes.22.2.11