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Five heating substations totaling about 29,178 m² and 2,156 kW of heat load in Chaxingshan Town, Horqin Right Front Banner, Hinggan League, Inner Mongolia. A mix of OYRR screw PLUS, low-ambient scroll, two-stage screw and all-in-one units holds 60°C water output even at -12°C outdoor temperature.

5 sites                   Heating substations
29,178 m²          Total heated area
2,156 kW             Total heat load
-35 °C                    Min. outdoor design temp.

Project Profile

1. Background: clean heating at the foot of the Greater Khingan Range

Chaxingshan Town sits at the southern foot of the Greater Khingan Range in Inner Mongolia, where winters are long and severe and extreme lows drop below -35°C. District heating was historically provided by small coal-fired boilers with low efficiency and heavy emissions. The local government pushed a "coal-to-electricity" clean-heating program, calling for an air-source heat pump system that still delivers stable hot water at extreme low temperatures and runs reliably for years.

This project covers five sites in town: the largest is Tianyuan Residential (17,746 m²), followed by the Chaxingshan Reservoir admin building (6,000 m²), the former government office (2,958 m²), the health clinic (2,274 m²), and a duty room (200 m²). The sites are scattered and the loads range widely, so a single model cannot cover all five; the right answer is a mix matched to each substation's load.

The pain point: a "heating island" with no utility piping

Chaxingshan is only about 30 km from Ulanhot, but it sits in the mountainous southern foothills of the Greater Khingan Range, and neither the municipal district-heating pipe network nor the long-distance natural gas pipeline reaches the town. It is, in effect, a "heating island":

• No district heating to tap into: the big-city cogeneration plant's heat network does not extend to mountain townships, so each site—the residential compound, the government office, the clinic, the reservoir building—has to source its own heat.

• Historically small, scattered coal boilers: each site ran its own low-efficiency coal boiler, heavy on smoke, ash and emissions—exactly what the coal-to-electricity policy aims to phase out.

• Piped gas is neither available nor affordable: without a gas main, LNG must be trucked in over long distances, driving gas prices up and supply reliability down; gas boilers simply do not pencil out economically.

"No heat pipe in, coal being phased out, gas too expensive"—against that backdrop, an air-source heat pump that needs no heating grid, no gas line, and just a local 380 V power supply is virtually the only viable route to clean district heating for a township like Chaxingshan.

Fig. 1 — OYRR air-source heat pump units on site: white cabinets, copper heat-exchanger coils, black top fan cowls, against a red-soil slope.

2. The solution: right-sized units per substation

OYRR sized 12 units by the floor area and heat load of each of the five sites, using "screw for the big load, scroll for the mid load, two-stage for extreme cold":

① Screw PLUS for the largest load

Tianyuan Residential (17,746 m² / 1,244 kW) is the biggest load of the five. It uses two OY-DRD500LF/EB and one OY-DRD310LF/EB screw PLUS units with Hanbell screw compressors for high capacity and smooth continuous heating.

② Low-ambient scroll for mid-size sites

The former government office, health clinic and reservoir admin buildings (2,000–6,000 m²) use six OY-RD98AWF/TE low-ambient scroll units with enhanced vapor injection, stable down to -35°C, with flexible staging.

③ Two-stage screw + all-in-one for extreme cold and small loads

The reservoir site adds one OY-DRD460LF/C two-stage screw unit as a cold-weather backup; the 200 m² duty room uses two OY-RD13AWF/E all-in-one units that need no separate plant room.

Fig. 2 — Rooftop overview: OYRR units lined up and tied into a single insulated water loop.

3. Why 60°C water at -35°C ambient

Enhanced vapor injection + two-stage compression

Ordinary air-source heat pumps lose capacity sharply below -10°C and water temperature drops with it. The OYRR screw PLUS and low-ambient scroll lines use enhanced vapor injection to cool the discharge temperature; the two-stage screw unit runs two-stage compression with intercooling, holding stable operation at -35°C and delivering 60°C water at -12°C outdoor — directly compatible with existing radiator systems, no terminal upgrade needed.

Patented non-reversing defrost

Traditional reversing-valve defrost blows cold air into the room and swings water temperature. OYRR's patented non-reversing defrost (ZL202020347772.3) keeps refrigerant flow direction unchanged during defrost, so room temperature stays steady.

Siemens PLC central control

All 12 units across five sites connect to a Siemens PLC, showing each site's temperature, frequency and defrost status on one screen, adjustable remotely — no need to walk each site to inspect.

High efficiency: IPLV(H) 22% above Grade-1

The units' integrated part-load value IPLV(H) is 22% above the China national Grade-1 line, which matters across the five-month heating season.

Fig. 3 — Side view: white-cabinet units lined up under a clear northern winter sky.

Note: figures describe a single project. Actual water temperature and energy use depend on building insulation, terminal type, occupant behavior and local weather; each new project must be re-sized on local design data.

4. Three notes for northern coal-to-electricity projects

1. Size units per substation, not one model for all

A 30,000 m² district heating program usually covers residential, office, medical and duty buildings with loads from 20 kW to 1,200 kW. Screw for the big load, scroll for the mid load, two-stage for extreme cold is more economical than forcing one model everywhere.

2. Size to the local extreme low temperature

Stable operation at -35°C and 60°C water at -12°C is the pass line for northern coal-to-electricity projects. Select directly against the extreme low ambient, not just nominal nameplate conditions.

3. Defrost method directly affects room comfort

Reversing-valve defrost blows cold air indoors and swings water temperature. A non-reversing defrost design is better for residential and health-clinic sites that cannot tolerate room-temperature swings.

FAQ: northern clean heating

Can air-source heat pumps heat at -35°C?

Yes. On this project in Chaxingshan, Inner Mongolia, 12 OYRR air-source heat pumps run stably at -35°C outdoor and deliver 60°C water at -12°C outdoor, directly connected to radiator systems.

Why 12 different models for 30,000 m²?

Because the five sites range from Tianyuan Residential (17,746 m² / 1,244 kW) to the duty room (200 m² / 20 kW). Matching units per site is cheaper and more efficient than one oversized model everywhere.

What does the US$375,278 equipment price include?

It is EXW (incl. VAT) for the 12 OYRR outdoor units, the Siemens PLC central control system and random accessories. It does not include on-site piping, pumps, insulation, installation or power distribution.

Is running cost high during the heating season?

With IPLV(H) 22% above Grade-1 and northern coal-to-electricity tariff policies, a heating season's running cost is typically below that of a traditional small coal boiler.

How long is the warranty?

24 months whole-unit; the Hanbell screw compressor follows the manufacturer's terms.

5. About OYRR

OYRR (Guangdong Eurasian Refrigeration Equipment Manufacturing Co., Ltd.) manufactures refrigeration and heat-pump equipment covering air-source heating heat pumps, industrial water chillers, ultra-low-temperature heat pumps and food cold-storage refrigeration units, exported to the Middle East, Southeast Asia, Latin America and Europe. The 12 outdoor units and Siemens PLC central control for this project were supplied by OYRR.

Ultra-low-temperature air-source heat pump

Stable at -35°C, enhanced vapor injection with Hanbell screw compressor, patented non-reversing defrost, IPLV(H) 22% above Grade-1, 24-month whole-unit warranty.

Source: project proposal YY230609B001 and on-site photographs. Figures describe a single project and depend on building insulation, terminal type and outdoor weather; they are provided as a reference for similar projects.