In the ultra-low temperature of【 -40℃ 】in winter, Airosd air source heat pump relies on hard-core technology and uses ultra-low temperature constant temperature units to provide 【hot water for bathing】 in resort hotels, and provides 【Bathroom hot water heating】 services for【 indoor swimming pools 】and【open-air swimming pools】, ensuring the water temperature. of constant comfort.
It gives tourists a comfortable leisure experience while greatly reducing the hotel's energy costs.
Resort hotel project — AIROSD Northeast Nitou Mountain Hot Spring Hotel Project: Geothermal-Coupled Intelligent Heat-Pump Water System Revolution
At the foot of Nitou Mountain in Northeast China’s severe-cold region, the AIROSD Hot Spring Hotel project innovatively integrates natural hot springs with intelligent heat-pump technology, reengineering the hotel’s hot water for bathing and Pool water heating systems. Covering 38,000 m², the project achieves a sector-leading overall annual energy savings rate of 51.3% through a four-tier energy utilization strategy.
Innovations in the hot water for bathing system
The hotel’s 412 guest rooms use a dual-loop Bathroom hot water heating design:
Main loop — direct spring supply
The natural hot spring, after purification, feeds bathtubs directly (maintained at 42°C), preserving over 92% of mineral content.
Auxiliary loop — intelligent heat pumps
Eight variable-frequency air-source heat pumps ensure supply under extreme weather. A stratified thermal storage tank stores heat with top/bottom layers controlled at 65°C / 45°C. The Bathroom hot water heating system achieves a 100% instant-hot rate for hot water for bathing, with an energy cost of only RMB 0.8/ton (compared with RMB 4.2/ton for conventional electric heating). VIP hot-spring suites are fitted with intelligent Bathroom hot water heating terminals that preheat 15 minutes before use, dynamically adjust massage water temperatures, and monitor water consumption in real time.
Key technologies for stable pool temperatures
Indoor pools (indoor swimming pools)
A 25 × 12 m competition-grade pool adopts an innovative “spring water + heat pump” dual-source approach: indoor swimming pools temperature control reaches ±0.3°C accuracy; indoor swimming pools humidity is maintained at 60% ± 5%; indoor swimming pools annual energy savings reach 68%.Outdoor pools (open-air swimming pools)
Three landscape hot-spring outdoor pools are staged at 42°C / 38°C / 35°C. Breakthrough antifreeze measures include a nano thermal-insulating membrane on the water surface (reducing heat loss by 40%) and an edge-jet heating system to prevent icing around the perimeter. As a result, open-air swimming pools remain operable even at −25°C ambient.
System integration and operational data
An energy management system (EMS) integrates five subsystems: graded hot-spring utilization, Bathroom hot water heating network, indoor swimming pools environmental control, open-air swimming pools anti-freeze system, and tail-water waste-heat recovery. The 2023 winter operation report shows:
hot water for bathing system:
hot water for bathing daily supply: 210 tonnes
average energy consumption: 0.78 kWh/tonne
failure rate: < 0.3 incidents/month
Technical breakthroughs and industry value
Four-stage hot-spring resource utilization:
78°C source water → high-temperature soaking pools
62°C tailwater → Bathroom hot water heating
45°C discharge → indoor swimming pools
30°C tailwater → preheat open-air swimming pools
Innovations in Pool water heating for extreme cold:
Developed anti-freeze titanium heat exchangers capable of normal operation at −35°C.
Pool water heating incorporates surface radiation loss suppression technologies.
Subfloor heating auxiliary system at a power density of 80 W/m².
A coupled hot-water / pool model was established: Pool water heating reuses shower wastewater to preheat pool makeup water (saving 120 tonnes/day). Dehumidifier condensate from pools is used to pre-treat water for hot water for bathing. The integrated system attains a combined COP of 6.2.
Economic and environmental results
The project reduces annual operating costs by RMB 2.86 million and cuts CO₂ emissions by 1,150 tonnes. The indoor swimming pools and open-air swimming pool achieved year-round utilization rates of 98.7% and 81.5% (in winter), respectively, becoming a benchmark for high-end hot-spring hotels in the Northeast. AIROSD’s integrated solution provides a sustainable technical paradigm for hospitality operations in cold regions.
