Yes, solar blankets do work at night, although their function differs from their daytime role.
According to the reference from HowStuffWorks, a swimming pool solar cover, also known as a blanket, is designed to perform dual functions: it captures solar energy to heat the pool during the day and maintains its temperature at night.
How Solar Blankets Function at Night
While a solar blanket cannot create heat after the sun goes down, its key purpose during the night is to conserve the heat the pool gained during the day.
Nighttime Mechanism
The primary way a solar blanket works at night is by acting as an insulating layer on the water's surface. This layer significantly reduces heat loss through:
- Evaporation: Water evaporation is a major cause of heat loss from a pool. The blanket covers the surface, preventing this process.
- Convection: It limits the contact between the warmer pool water surface and the cooler night air, reducing convective heat transfer.
Benefits of Using a Solar Blanket at Night
Utilizing a solar blanket overnight offers several advantages:
- Temperature Retention: It effectively holds onto the heat absorbed from the sun throughout the day, preventing the water temperature from dropping significantly overnight.
- Warmer Mornings: The pool will be noticeably warmer the next morning compared to a pool left uncovered, making it more inviting for an early swim.
- Energy Savings: By retaining heat, it reduces the energy needed to reheat the pool, whether from the sun the next day or a pool heater.
- Water Conservation: Reducing evaporation also means less water is lost from the pool.
Daytime vs. Nighttime Role
Here is a comparison of how a solar blanket works during the day versus at night, based on its described functions:
| Aspect | During the Day | At Night |
|---|---|---|
| Heat Generation | Yes (Absorbs solar energy) | No |
| Pool Temperature | Heats water | Maintains temperature |
| Primary Function | Solar Heat Collection | Insulation & Heat Retention |
Therefore, while they don't heat at night, their function of maintaining temperature is essential for maximizing the comfort and efficiency benefits gained from daytime solar heating.
