Solar Heating Project for Minning Energy-Saving Office Building, Yinchuan

In Minning Town, Yinchuan (Ningxia), where winter temperatures drop to -15℃ and heating lasts 5 months, the 285㎡ Minning Energy-Saving Office Building once struggled with traditional electric heating: over 3,000 yuan/month (15,000 yuan/year) in costs, and sharp temperature gaps (below 16℃ in corners). Now, a solar heating system with 48 flat-plate collectors has turned it into a "warm, low-carbon" green building model.

Background: Dual Demands Lead to Solar Choice

Minning Town has a temperate continental climate, with long cold winters (Nov-Mar). As a local "green energy-saving demo project", the office building needed a solution that resists -15℃ cold, stabilizes temperatures, and cuts costs. Leveraging Yinchuan’s 2,800 annual sunlight hours, the "solar-led, electric-assisted" system was selected—it uses local clean energy and handles extreme weather.

Core System: Cold-Resistant Collectors for the Northwest

The system’s core is 48 flat-plate collectors (2㎡ each, total 96㎡), meeting over 80% of winter heating needs. Installed in "series + parallel" on the south roof (35° angle for max sunlight), they connect to indoor floor heating. When solar radiation hits 300W/㎡, water heats to 50-60℃, raising indoor temps from 10℃ to above 18℃ in 2-3 hours (sufficient for sunny days).

For cloudy/snowy weather, a "temp-difference sensing + electric auxiliary" module works: a 3kW heater starts if the temp gap is below 5℃, and a 500L tank stores hot water. Even on 2 consecutive cloudy days, auxiliary power use is only 15kWh/day—far less than traditional systems.

Results: Triple Upgrades

Since winter 2023, the system has performed well:

• Comfort: Floor heating keeps temp differences within ±2℃ (20℃ in offices/meeting rooms, above 18℃ in reception areas); zoned control (22℃ for used rooms, 16℃ for vacant) adds flexibility.

• Costs: Significant savings ease financial burdens.

• Ecology: It cuts 13,000kWh electricity/year (10.2 tons CO₂), with 8.16 tons direct carbon reduction (80% solar heating). It also lowers sulfur dioxide and nitrogen oxide emissions.

Significance: A Replicable Model

1. Proves solar heating works in -15℃ cold regions, breaking the "only for south" myth.

2. Offers a low-cost, modular solution for small/medium public buildings (town offices, community centers), lowering renovation thresholds.

3. Aids grassroots "dual carbon" goals by using local solar resources, driving energy transition in northwest counties.