Cooling towers allow transferring of processed waste heat to the atmosphere. They are an important part of any production system and proper functioning and structural stability must be assured. As the industry leader in concrete repair and protection, Sika can provide long lasting construction and refurbishment solutions to prolong the longevity of cooling towers, offering strategies which avoid the need for numerous shutdowns.
Environmental Impact Criteria
CED accounts for the consumption of energy resources, namely the primary energy from renewable and non-renewable resources. GWP measures the potential contribution to Climate Change, focusing on emissions of greenhouse gases, such as carbon dioxide (CO₂). POCP is the potential contribution to summer smog, related to ozone induced by sunlight on volatile organic compounds (VOC) and nitrous oxides (NOx).
Cooling Down Environmental Impacts
A construction project with a surface of 20,000 m² for a time period of 60 years was analysed for three refurbishment strategies: a traditional system (scenario 1) and two Sika State of the Art systems (scenarios 2 and 3).
|Material efficient||Time efficient||Overall cost efficient||VOC content|
|1 Traditional||Polymer and solvent based products
4 full refurbishments (4 shutdowns)
|2 Sika state-of-the-art||Polymer and solvent based products
1 full refurbishment and 1 maintenance (refreshing) (2 shutdowns)
|3 Sika state-of-the-art||Polymer and solvent based products
Resurfacing and protection at new construction and 2 maintenances (refreshing) (2 shutdowns)
QUALITATIVE CHARACTERIZATION OF THE SCENARIOS
Legend_ - very low, + low, ++ average, +++ high, ++++ very high
RESULTS AND CONCLUSIONS
To depict the environmental impacts from both scenarios, they were compared through Life Cycle Assessment (LCA). The LCA is from cradle to grave, which means it investigates the potential environmental impacts from raw material acquisition, production, use, to end-of-life treatment, and final disposal.
To illustrate the environmental impacts from both scenarios, the Cumulative Energy Demand (CED), the Global Warming Potential (GWP) and the Photochemical Ozone Creation Potential (POCP) were determined.
1. More than 60 and 80% of Material Savings
Scenario 1 uses products of lower quality and therefore full refurbishments need to be repeated every 10 years (total 4 times). On the other hand, scenarios 2 and 3 use products of higher quality, reducing the refurbishment frequency and the material intensity, generating more than 60 and 80% of material savings, respectively. Both are material efficient and time saving solutions, which avoid solvent-based traditional protection coatings.
Thanks to the full refurbishment in scenario 2, the service life is prolonged for further 20 years, after which only refreshing of the coats are needed. In scenario 3 the refurbishment time is further reduced by resurfacing and protecting directly after construction, after which only refreshing of the coats is needed (total 2 times).
2. Higher Resource Efficiency
Scenario 1 has significantly higher environmental impacts, as it is more material intensive than scenarios 2 and 3. These also replace solvent based outer shell coats with water based coats and use solvent based inner coats of reduced VOC content.
3. More Sustainable Value
To show the overall environmental and economic performance of Sika State of the Art systems vs. traditional systems, a relative comparison for the main sustainability drivers in refurbishment (materials, time, costs, GWP, CED, POCP) is shown below. Both Sika state of the art systems have a better overall performance, especially scenario 3.