## 1 Introduction  
The use of fossil fuels has serious negative impacts on the environment. These impacts include increased carbon dioxide emissions, air pollution, and far-reaching consequences for biodiversity and human health. The transition to renewable energy and sustainable practices is therefore essential to overcome these challenges and protect the health of our planet and its inhabitants. By 2021, Austria aimed to have 36.4% of its gross final energy consumption coming from renewable sources [1]. One of the major technological challenges in utilizing renewable energy is harmonizing the fluctuating and uncontrollable supply profiles of solar and wind power with consumer energy demands, ensuring a cost-effective and consumption-oriented supply of electricity and heat [2]. Thermal energy storage, in particular, plays a crucial role in achieving a renewable and efficient energy supply, given that the heating and cooling sector accounts for nearly 25% of global energy production [3]. Thermal energy storage technologies can be categorized into three primary systems: sensible, latent, and therochemical. Latent energy storage systems make use of phase change enthalpies during phase transitions. Here, a constant temperature is maintained throughout the melting process of pure substances, like fatty acids, paraffines, and salt hydrates. In agriculture, cold winters present the challenge of protecting plants from frost damage. Frost occurs when water vapor condenses from saturated air and freezes on solid surfaces at low temperatures, posing a significant threat to most fruit crops, particularly during spring when bud formation increases frost sensitivity [4]. Frost damage can cause substantial delays in leaf and fruit development, leading to considerable yield losses [5]. Therefore, effective frost protection is essential to ensure stable yields and high fruit quality. All frost protection methods aim to prevent or replace radiant heat losses. The choice of appropriate frost protection technology depends on various factors, including acquisition and operating costs, personnel requirements, and availability. Conventional methods such as heaters and aerators have high energy consumption (e.g., heating oil, electricity), while irrigation systems entail significant investment costs and risks of flooding and soil saltation [4]. The susceptibility of most fruit crops to frost-induced damage is well documented. Of notable concern is the occurrence of spring frost, which poses a significant threat to fruit crops. While deciduous trees generally exhibit resilience to winter frost, their vulnerability escalates markedly during the formation of buds in spring [6]. Hence, implementing strategies to shield nascent buds from sub-zero temperatures becomes imperative for safeguarding crop yields. Also, providing the right temperature for crop roots stimulates plant development and flower production, increasing productivity [7]. The optimal root temperature varies from plant to plant. The ideal root temperature for tomato plants is located between 15 \({}^{\circ}\)C and 25 \({}^{\circ}\)C [8]. It is located between 17 \({}^{\circ}\)C and 24 \({}^{\circ}\)C for leaf lettuce [9]. For other crops such as tobacco, cotton, corn, and peas, the ideal root temperature is close to 32 \({}^{\circ}\)C, 25 \({}^{\circ}\)C, 20 \({}^{\circ}\)C, and 10 \({}^{\circ}\)C, respectively [10]. Apples are less sensitive to frost than cherries, plums, and peas. Various methods can be used to protect plants against late frost events: paraffin candles, solid fuel stoves, and mobile and fixed gas heaters. These solutions are costly, difficult to implement, and polluting. Furthermore, the effectiveness of these methods in rugged terrain is difficult to assess [11]. An effective method is frost irrigation, where up to 40 m\({}^{3}\) of water is sprayed over the trees, per hour and per hectare.