This invention relates to the field of Water Generation systems from atmosphere. It describes the integration of an intelligent DC Compressor driven either by direct photovoltaic system/Grid 20 power or by the stored energy from the Battery to enhance the efficiency of the atmospheric water
Generator.
Background
25 Access to clean and safe drinking water is a critical global challenge, exacerbated by climate change, population growth, and increasing water scarcity. Traditional water sources such as rivers, lakes, and groundwater are becoming increasingly unreliable, necessitating innovative solutions for water generation. Atmospheric Water Generation (AWG) technology offers a promising approach by extracting water vapor from the atmosphere and condensing it into liquid water. 30 Conventional AWG systems predominantly rely on energy-intensive refrigeration cycles or passive desiccant-based methods in which the yield is very low. These systems often underperform in regions with low ambient humidity levels, and their energy demands can limit their practicality and sustainability. Hence energy efficiency needs to be enhanced to make it commercially viable
in a large scale.

In a prior art with the publication in Energy Conversion and Management 314 (2024) 118666,
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titled “Zero-Brine Discharge System for Atmospheric Water Generation”, an AWG is developed using atmosphere as a reliable water source, thereby eliminating the need for continuous seawater
input and brine disposal.
40
The prior art with patent grant number “US 10,829,913 B l” titled “Hybrid Potable Water Generator”, uses heat pump cycle for water generation, that allows for efficient usage of energy
with minimal wastage.
45 In the prior art with patent grant number “US 2021/0162314 A l”, title “Atmospheric Water Generator System and Method”, a comprehensive system is designed for efficient and user- friendly potable water generation with robust tracking and interaction capabilities.
In one of the prior arts US12286773B2 titled Atmospheric Water Generator (AWG) discloses a 50 device that extracts potable water directly from ambient air. As a recent AWG patent, it focuses on improving efficiency, reliability, and practicality compared with earlier designs. It typically addresses energy usage, condensation performance, and integration of air treatment or filtration
stages.
55 In another prior art US20230277957A1 titled Atmospheric Water Generator with Compressor discloses a system designed to extract potable water from ambient air using a thermodynamic cycle driven by a compressor. The invention targets more efficient, scalable, and integrated water generation solutions for off-grid or hydrogen-fuel applications.

In yet another prior art US11679339, titled “High-output atmospheric water generator,” covers a 60 large-scale atmospheric water generator (AWG) system that extracts potable water from ambient air using an advanced vapor-compression refrigeration cycle with compact screw compressors. It aims to- deli ver much higher water output and efficiency than conventional AWGs, targeting---------applications where local clean water is scarce.
65 In further another prior art US20250186941 titled “Atmospheric Water Generator with Water Cooling System” describes a condensing-type atmospheric water generator (AWG) that integrates a dedicated water-based cooling loop to improve efficiency, particularly in warm, humid
environments.
70 We can conclude from this, that by leveraging renewable energy sources and optimizing the water harvesting process, the above inventions present a sustainable and reliable solution to the global water scarcity crisis. The current patent relates to improving the efficiency of such AWG systems operated by Solar PV system /Grid power by different modes of operation described herein.
75 Objective:
The main objective of the present invention is to improve the efficiency of Solar / Grid integrated Atmospheric Water Generator appreciably through the integration of an intelligent DC
compressor.
80
It is another objective of the present invention to integrate a battery storage to enable the operation of the AWG system during the night time when Relative Humidity (RH) of air is usually higher in
the atmosphere.

Brief Description of the Drawings: Figure 1 illustrates the working principle of the present invention
A- Solar PV module B- Battery Storage Unit C- Intelligent DC compressor D- Evaporator E- Condenser F- Expansion Device
Detailed Description of the Invention
The present invention relates to a solar-powered atmospheric water generator (AWG) system based on a vapor compression refrigeration cycle utilizing a direct current (DC) compressor configured to operate directly on DC power generated from a solar photovoltaic (PV) source. The system is designed to eliminate the need for DC-AC conversion, thereby minimizing energy losses, simplifying system architecture, and improving overall efficiency.
As illustrated in Fig. 1, the system comprises a solar PV module (A), a battery storage unit (B), a DC compressor (C), an evaporator (D), a condenser (E), and an expansion device arranged in a closed-loop refrigeration circuit The solar PV module generates DC electrical power, which is supplied either directly to the DC compressor or stored in the battery storage unit for subsequent use. The DC compressor is electrically coupled to the PV module and/or the battery without the

use of an inverter. Alternatively provision is also made to convert the Grid AC power to DC power
to operate the compressor.
110 In operation, ambient air is drawn over-the evaporator (D) by a forced air mechanism, .such as.an axial fan, wherein moisture present in the air condenses on the surface of the cooling coil to form water. The refrigerant circulating through the evaporator absorbs latent heat and is subsequently compressed by the DC compressor (C). The compressed refrigerant is then directed to the condenser (E), where heat is rejected to the surrounding environment, causing the refrigerant to 115 condense. The condensed refrigerant is expanded through an expansion device, such as a capillary tube, to reduce its pressure and temperature before being recirculated back to the evaporator to
repeat the cycle.
A key feature of the invention is the use of a variable-speed DC compressor configured to operate 120 over a wide range of input voltages corresponding to fluctuations in solar irradiance. A control unit is provided to regulate compressor speed using pulse-width modulation (PWM) and/or voltage-based control, enabling the compressor to dynamically adapt to real-time power availability. This ensures continuous and energy-efficient operation without reliance on complex power conditioning systems. Optionally, a maximum power point tracking (MPPT) controller may 125 be employed to optimize solar energy utilization.
The battery storage unit (B) preferably comprises lithium-ion batteries characterized by high energy density, long cycle life, and rapid charge-discharge capability. A battery management system (BMS) is integrated to monitor and regulate parameters including state of charge (SOC),

voltage, and temperature, thereby ensuring safe and efficient operation. The battery is configured to store excess energy generated during peak sunlight hours and supply power to the compressor during periods of low or no solar irradiance, particularly during nighttime or early morning hours ■ when atmospheric relative humidity is higher and ambient temperature is lower, thereby enhancing
condensation efficiency and water yield.
135
In a preferred embodiment (best mode), the system includes two solar PV modules rated at 600 Wp with an output voltage range of 18-36 V DC, a 24 V variable-speed hermetically sealed DC compressor having a power rating of 250 W, and a refrigerant selected from Rd 34a. The evaporator comprises a fin-and-tube heat exchanger made of copper tubes and aluminium fins with an 140 effective surface area density in the range of 400 m2 /m3. The condenser is an air-cooled finned heat exchanger provided with a fan for forced convection. The expansion device is a capillary tube having an internal diameter of approximately 0.8 mm and a length of 1.5 meters. The battery storage unit comprises a 24 V, 200 Ah lithium-ion battery pack integrated with a BMS. An axial fan with a capacity of approximately 100-200 cubic feet per minute (CFM) is used to draw humid
145 air across the evaporator surface.
During daytime operation, the DC compressor is powered directly by the solar PV module, with its speed automatically adjusted based on the available solar power. Excess energy generated is stored in the battery. During nighttime or low irradiance conditions, the system operates using 150 stored battery energy, enabling continuous operation and improved water generation due to
favourable ambient conditions.

A prototype system based on the above configuration was developed and tested under controlled environmental conditions. The test was conducted at an ambient temperature of 30°C ± 2°C and relative humidity of 65% to 75%, with solar irradiance ranging from 600 to 900 W/m2 during the -peak-sunshine hours. The system produced approximately 20 litres of water per day withan energy consumption of about 0.3 kWh per litre. In comparison, a conventional 350 W AC compressor­based AWG system operating under similar conditions produced approximately 15 to 18 liters per day with an energy consumption of 0.5 kWh per litre.
The experimental results demonstrate that the present invention achieves a reduction in energy consumption of approximately 40% per liter of water produced. These improvements are attributed to the elimination of inverter losses, efficient utilization of direct DC power, and adaptive variable­
speed operation of the compressor.
The system may further be configured to operate in a hybrid mode using both solar PV power and grid electricity to ensure uninterrupted operation. Additionally, the solar PV module may be structurally integrated with the AWG unit to form a compact and portable system suitable for deployment in remote or off-grid locations, including applications for military personnel, disaster
relief operations, and trekking activities.

A solar-powered atmospheric water generator (AWG) system based on a vapor compression refrigeration cycle, comprising: a solar photovoltaic (PV) module (A) configured to generate direct current (DC) power; a DC compressor (C) directly coupled to the solar PV module; an evaporator (D) configured to condense moisture from ambient air; a condenser (E) configured to reject heat to the surroundings;
an expansion device (F);
a battery storage unit (B) electrically connected to the solar PV module; and a control unit configured to regulate operation of the DC compressor, wherein the DC compressor is configured to operate at variable speed based on available DC input power from the solar PV module and/or the battery storage unit to optimize energy consumption and water yield.
2. The AWG system as claimed in claim 1, wherein the DC compressor is configured to operate over a variable input voltage range corresponding to fluctuations in solar
irradiance.
3. The AWG system as claimed in claim 1, wherein the control unit is configured to regulate compressor speed using pulse-width modulation (PWM) and/or voltage-based
control

The AWG system as claimed in claim 1, wherein the system further comprises a maximum power point tracking (MPPT) controller configured to optimize power extraction from the solar PV module.
5. The AWG system as claimed in claim 1, wherein the battery storage unit comprises a lithium-ion battery pack and a battery management system (BMS) configured to monitor and regulate state of charge, voltage, and temperature.
6. The AWG system as claimed in claim 1, wherein the battery storage unit is configured to store excess energy generated during peak solar irradiance and to supply power to the DC compressor during low or no solar irradiance conditions.
7. The AWG system as claimed in claim 1, wherein the expansion device comprises a capillary tube configured to reduce pressure and temperature of the refrigerant prior to
entry into the evaporator.
8. The AWG system as claimed in claim 1, wherein the system further comprises an air circulation mechanism configured to direct ambient air over the evaporator to enhance
moisture condensation.
9. The AWG system as claimed in claim 1, wherein the solar PV module is structurally integrated with the AWG system to form a compact and portable unit.

The AWG system as claimed in claim 1, wherein the system is also configured to operate in a hybrid mode using solar PV power and grid power.
11. A method of generating water from atmospheric air using the AWG system as claimed
in claim 1, comprising:
generating DC power using a solar photovoltaic module; directly supplying the DC power to a variable-speed DC compressor without inverter
conversion;
compressing and circulating refrigerant through a vapor compression cycle; cooling ambient air in an evaporator to condense moisture; collecting the condensed water; storing excess electrical energy in a battery storage unit; and operating the system using stored energy during periods of low or no solar irradiance.
12. The method as claimed in claim 11, wherein the speed of the DC compressor is dynamically adjusted based on available solar power and battery conditions.