Why Evaporation Is Expensive in Biogas Systems
Anaerobic digestion depends on biological stability. When a lagoon or digester loses heat through an uncovered liquid surface, supplemental heating systems must replace that energy to maintain the target operating range. In cold weather, wind and dry air can accelerate evaporation and make the surface a major pathway for heat loss.
A floating cover reduces direct air-water contact, blocks wind-driven vapor transfer, and can add insulation above the liquid surface. For biogas operators, that means the cover can support three goals at once: lower evaporative heat loss, more stable process temperature, and reduced odor release from the surface.
Where Floating Insulation Is Most Useful
- Heated anaerobic digesters where maintaining process temperature is a recurring operating cost.
- Biogas lagoons in cold climates where winter heat loss can reduce biological activity and methane production stability.
- Dairy manure lagoons where odor, ammonia, and heat retention are all relevant design concerns.
- Industrial process ponds where warm water must be retained before treatment, reuse, or discharge.
Product Options for Biogas and Heated Ponds
| Product | Best Fit | Thermal Role | Wind / Coverage Notes |
|---|---|---|---|
| Hexprotect® MAX R | Highest-insulation floating cover for heated digesters and cold climates | R-17+ closed-cell foam insulation | Up to 99% surface coverage; best for moderate-wind heated applications |
| Rhombo Hexoshield® 66 | Hybrid cover where insulation and high wind resistance are both priorities | R-4 insulation | High evaporation reduction with water-ballasted wind resistance |
| Rhombo Hexoshield® 189 | Maximum buoyancy and stronger wind exposure with insulation | R-8 insulation | Heavy-duty hybrid panel for more demanding liquid containment sites |
| Hexprotect® AQUA | Non-insulated surface coverage for odor, algae, evaporation, and wildlife control | Evaporation and surface barrier rather than thermal insulation | Up to 99% coverage and 130+ MPH wind resistance |
How to Specify the Cover
Start with the process temperature requirement
If the liquid must stay above ambient temperature, an insulated cover should be evaluated before a standard evaporation-control cover. Hexprotect MAX R is the primary AWTT option when insulation is the central performance requirement.
Separate insulation needs from gas-capture needs
Modular floating covers are not gas-tight collection covers. If the project requires sealed methane capture, pressure management, or gas routing to a flare or engine, that requirement should be handled by a purpose-designed gas collection system. Modular covers are best evaluated for evaporation control, heat retention, odor suppression, and surface protection.
Match wind exposure to the product family
Heated lagoons in open terrain may need a balance of insulation and wind resistance. In those cases, compare Hexprotect MAX R against Rhombo Hexoshield variants using the same wind, fetch, temperature, and water-value assumptions.
Why AWTT Fits Biogas and Anaerobic Applications
AWTT offers both high-insulation and high-wind modular cover options, which lets the engineering team match the cover to the actual operating constraint. A sheltered heated digester and an exposed lagoon do not need the same product.
For a deeper thermal comparison, see Insulated vs. Non-Insulated Floating Covers. For industry-specific applications, see Biogas & Anaerobic Digesters and Floating Insulation.
Design Inputs to Collect
- Operating temperature range and whether heating is continuous or seasonal.
- Current heating fuel or energy cost for the lagoon, digester, or process pond.
- Surface area, average liquid depth, and seasonal water level variation.
- Wind exposure, fetch distance, and winter design conditions.
- Whether the project needs insulation only, odor control, wildlife exclusion, or gas-tight collection.
FAQs
Why does evaporation matter in biogas digesters?
Evaporation removes both water and heat. In heated digestion systems, reducing evaporation can lower the amount of supplemental heat required to maintain the target process temperature.
Which AWTT cover is best for heated biogas applications?
Hexprotect MAX R is the highest-insulation AWTT floating cover, with R-17+ insulation. Rhombo Hexoshield variants should be evaluated when the site also needs stronger wind performance.
Are modular floating covers gas-tight biogas collection covers?
No. Modular covers are not monolithic gas collection covers. They are appropriate for evaporation control, heat retention, odor suppression, and surface coverage, while sealed gas collection requires a separate purpose-designed system.