The global data center industry faces a convergent crisis: cooling accounts for 30-50% of facility energy consumption, while traditional synthetic refrigerants used in Computer Room Air Conditioners and chillersincluding R-410A (GWP = 2,088) and R-134a (GWP = 1,430)-are now banned for new data center installations under the U.S. AIM Act (effective January 2025) and EU F-Gas Regulation. This mandatory regulatory transition, combined with AI accelerator heat densities exceeding 700W per chip, creates a structural opportunity for CO₂ (R-744) natural refrigerant cooling: GWP = 1, zero ozone depletion, superior thermodynamic properties at high heat flux, and near-zero water consumption versus 1.8-9.5 L/kWh for evaporative alternatives. This paper presents RTSC (Rapid Technology System Cooling), a Layer-2 blockchain attestation protocol on Ethereum that quantifies, verifies, and tokenizes cooling efficiency improvements achieved through natural refrigerant systems. RTSC introduces a novel three-dimensional Cooling Efficiency Unit (CEU): energy efficiency (CEU-E), refrigerant environmental impact (CEU-R-a new metric capturing GWP elimination with no equivalent in existing standards), and carbon avoidance including waste heat recovery (CEU-C). CEUs are minted exclusively from oracle-attested sensor data secured by FROST threshold signatures and Zero-Knowledge proofs. A Monte Carlo simulation (n = 10,000) projects median PUE improvements of 35%, 100% WUE elimination (closed CO₂ loop), and 99.95% refrigerant GWP reduction. A game-theoretic analysis proves baseline manipulation is economically irrational. Economic sensitivity analysis identifies a break-even token price of $2.48-$4.38, with positive energy savings NPV independent of token price for median facilities.
Reducing energy and associated greenhouse gas emissions in buildings is one of the key aspects of climate change on a global level. To put the building sector on a low carbon development path, policies and adequate financing play a crucial role in each region. In the global South, policies and regulations related to the decarbonization of the building stock are increasingly being implemented. For policy and decision makers, adequate data on the status quo of the building stock, as well as the quantification of energy reduction measures, are essential to make informed decisions on the building regulatory and funding framework. The objective of this study is to provide data-driven insights into the potential for energy and CO2 reduction in buildings across various hot climate zones in the Global South. A simulation-based approach was employed to model five different building types, ranging from residential homes to office buildings, under a variety of architectural and building services scenarios. The simulations were conducted using the dynamic building energy simulation tool EnergyPlus, which assessed the impact of various energy-saving measures under both current and projected future climate conditions. This study concludes that optimizing passive design features, such as improved windows, solar shading, and reflective surfaces, in conjunction with active systems like decentralized cooling units and renewable energy integration, can result in a notable reduction in energy demand and emissions. Our findings provide a robust basis for policymakers to develop targeted energy efficiency strategies for buildings in hot climate zones, which will play a crucial role in achieving climate goals in the Global South.
Heat supply using a heat pump belongs to the field of energy-saving, environmentally friendly technologies and is becoming increasingly widespread in the world. This technology, according to the conclusion of a number of authoritative international organizations, along with other energy-saving technologies (use of solar, wind energy, ocean energy, etc.), belongs to the technologies of the 21st century. The main heat costs for household needs in buildings during the cold season are heating costs. This is explained by the operating conditions of buildings during the cold season, when heat loss through the building envelope significantly exceeds internal heat release. Therefore, to maintain the required internal air temperature, buildings are equipped with heating units. During the cold season, to create and maintain thermal comfort in buildings, technically advanced and reliable heating installations are required. The use of the proposed heat pump system will improve the efficiency of autonomous heat supply to decentralized and remote residential and industrial facilities, service enterprises. In addition, the proposed combination of heat pump units and renewable energy sources expands the resource base of the heat pump heating supply system, making it less dependent on fluctuations in ambient temperature, which is very important for increasing the level of reliability of heat pumps.
A thermally activated absorption heat pump suitable for use in naval expeditionary Environmental Control Units, as well as residential space-conditioning, is developed. Waste heat characteristic of the exhaust stream from a diesel engine GenSet is used to drive an absorption cycle to provide cooling. The heat source is coupled to the heat pump using an intermediate fluid loop for flexible deployment. With minor modifications, the heat pump could also provide heating at high coefficients of performance, resulting in versatile functionality. This technology capitalizes on heat and mass transfer enhancement possible in microscale passages to provide a compact architecture for the components and the overall system. The working fluid pair with zero Global Warming Potential is contained within this assembly, reducing fluid inventories significantly over conventional systems. Quiet, reliable, long-life operation due to the absence of a compressor and the use of few moving parts are further critical distinguishing advantages. Modularity in cooling capacity has been demonstrated through scaling-up of component geometry and internal features and dimensions. The core technology was initially demonstrated with a proof-of-concept microscale absorption chiller measuring 200 × 200 × 34 mm and weighing 7 kg that delivered 300 W of cooling in laboratory tests. In the previous BEETIT project, the team made significant advances over the proof-of-concept. System and component designs with > 10× scale-up in capacity were developed, in a packaged unit capable of standalone operation with a semi-autonomous control system. A cooling capacity of 3.5 kW with a COP > 0.5 at an ambient temperature of 35°C was demonstrated for this natural gas-fired unit. Significant cost reductions in fabrication were achieved using low-cost brazing instead of diffusion bonding. In companion projects funded by the Southern Company and the Georgia Research Alliance, stamping and fluid forming techniques were investigated to fabricate microscale features instead of photochemical etching, thereby leading to significant cost reductions. In a follow-on effort funded by ARPA-E and NAVFAC, a 2.7 kW cooling unit was developed to provide cooling at a severe ambient condition of 51.7°C. The unit was driven directly by diesel engine exhaust heat. Innovative finned heat and mass exchangers for the ambient-coupled condenser and absorber were developed. In the present effort, a standalone, packaged and controllable 10.5 kW cooling capacity absorption chiller is developed. This demonstrates a 30× scale up from the proof-of-concept, thus validating the scalability of microchannel heat exchangers for absorption heat pumps. Autonomous operation algorithms demonstrated enhanced dynamic performance. The knowledge from previous projects was leveraged to develop novel component designs that further helped in miniaturizing the heat exchangers. All coupling fluids are hydronically coupled to aid flexible field deployment. The prototype unit provides design cooling capacity at high ambient temperature conditions of 44°C at COP > 0.6.
Open access
Advanced Thermodynamic Systems and Engines
Refrigeration and Air Conditioning Technologies
Thermodynamic and Exergetic Analyses of Power and Cooling Systems