Energy Conservation

3 Ways to Reduce Building Energy Consumption Through Water Treatment

February 21st, 2019

Building HVAC water treatment is one of the most overlooked, yet easiest method to improve building energy efficiency without upgrading equipment. The majority of buildings use water as a delivery system for heat. Chilled water systems exhaust heat from the building in summer months and boiler water systems add heat to the building in the winter months. According to Stats Canada, space heating and cooling accounts for over 50% of total building energy consumption and greenhouse gas emissions (GHG).

Space Heating Energy Usage
Heating and cooling accounts for over 50% of total building energy consumption

The rising cost of energy and growing concern about GHG emissions makes building energy consumption a major target for improvement. Energy managers and building owners often invest in major projects like upgrading pumps, boilers and chillers to improve efficiency. The payback on these projects can range from five to fifteen years, making them impractical for most operating budgets. Before looking to new equipment to improve building energy performance, simple water treatment solutions can improve building efficiency from 5 to 20% with an immediate payback. Check out the following three energy saving tips to maximize your building energy efficiency through water treatment.

  1. Maximize Cooling Energy Efficiency

Using the correct water treatment combined with a scheduled, automated blowdown will save between 5% to 20% on air conditioning energy costs. Evaporative cooling towers are the most cost-effective and most common technology for commercial air conditioning. These systems use water to collect heat from the buildings air handling units and exhaust that heat through a chiller and cooling tower.

Evaporative Cooling Tower
Correct water treatment can save between 5%-20% on cooling costs

Around 75 to 80% of heat is removed from the water through evaporation, leaving behind mineral content which builds up to form scale deposits on all heat transfer surfaces. According to the Association of Water Technologies, a credit card thickness or 0.75 mm of scale within the chiller tubes and other heat transfer surfaces will result in a 28% increase in energy consumption. For example, if a 500-ton cooling tower which operates 18 hours per day for six months of the year has a 0.75 mm thickness of scale deposit, the annual energy cost to cool the building would increase by over $30,000.

Chiller Tube Scale
0.75 mm of scale will result in a 28% increase in energy consumption

Advancements in water treatment chemistry and automation controls has enabled water treatment experts to limit efficiency loss due to scale deposits and optimize water usage. In addition to increased efficiency, proper treatment will minimize biological growth which is the primary cause for the spread of legionnaires disease. If the water system has been neglected, a water treatment company can offer the proper techniques to clean the system and restore efficiency while minimizing the risk for equipment damage and pinhole leaks. Contact a water treatment professional to design a cooling tower treatment plan that will best suit the buildings unique equipment, cooling demand and water supply. A small investment in a water treatment will payback instantly with building energy savings, increased heating and cooling capacity and longevity for your existing equipment.

  2. Minimize Boiler Energy Loss

Prevention and removal of corrosion and scale formation in boilers can result in significant energy savings. According to the U.S. Department of Energy, a 1/16” deposit of iron scale will result in 6.2 percent increase in boiler energy consumption. Corrosion inhibitor is added to the water in new boiler systems to prevent corrosion. Over time small leaks from equipment malfunctions and regular maintenance will cause the inhibited water to leak out and be replaced by raw water. The raw water is often oxygen rich with a low pH which is corrosive to the metals within the boiler system.

Oxygen Pitting
Corrosion inhibitor is added to system water to minimize energy robbing corrosion and scale

Unfortunately, mechanical contractors and building operators are often not trained to regularly test and maintain the boiler water quality. For this reason, boiler systems can go untreated for many years causing scale build up and corrosion to occur. Buildings owners are frequently unaware of the decreasing energy performance cause by the untreated corrosion issues and only become aware of the problem when expensive system repairs bring the issue to light. Local water treatment companies have service teams specifically trained to test, monitor and maintain inhibitor levels to prevent corrosion and energy efficiency loss. If a building has not maintained scheduled water testing and treatment, ask your local water treatment expert about chemical cleaning to remove the scale and deposits. Depending on the condition of the system, a cleaning, flush and treatment can result in 5-10% reduction in boiler energy consumption.

  3. Lower Energy Consumption Through Improved Heat Transfer

The most recent advancement in water treatment is a proactive solution which can improve energy efficiency beyond peak efficiency. The new solution reduces the surface tension of the HVAC system water to improve heat transfer and lower energy consumption. For decades, additives have been used in building HVAC water to reduce corrosion and add freeze protection. Now, advancements in water treatment additives have proven that surface tension reduction can improve energy efficiency by 10-20%. EndoTherm is a boiler or chilled water additive specifically designed to reduce water surface tension by 60% which increases the contact surface area available for heat transfer.

EndoTherm
EndoTherm is a boiler or chilled water additive which improves energy efficiency

In a boiler system treated with EndoTherm, more heat energy is transferred from the water into the room. The returning water then has less heat energy and returns to the boiler cooler. This cooler return water allows boilers to condensate more and reduces flu gas losses, creating ideal conditions for peak boiler efficiency. Independent verification and hundreds of case studies including projects with Simon Fraser University, Vancouver International Airport and Bentall Kennedy have shown that the addition of EndoTherm to a boiler or chiller water will result in a 10-20% reduction in system energy consumption.

YVR EndoTherm Project
EndoTherm reduced Vancouver Airport gas consumption by 17.32%

By reducing the water’s surface tension, even the most modern and energy efficient systems will use less fuel to maintain the desired temperature setpoint when compared with water or glycol systems. Reducing surface tension to improve heat transfer is not a new concept, but it has taken products like EndoTherm to make the innovative leap forward by finding a solution to improve heat transfer while remaining thermally stable and safe on all system materials and the environment.  

In buildings where water is the heat distribution highway, water treatment is the most inexpensive way to improve building energy efficiency. A minimal investment in water treatment will help manage scale deposits, corrosion control and reduce surface tension, saving money on energy bills and reducing the building’s carbon footprint. Before replacing costly HVAC equipment, start by optimizing the water system first.

by Will Wilson

Sustainability and Development Manager 

Useful Links:

PACE Chemicals Ltd

EndoTherm Energy Saving Additive

Cooling Tower Water Treatment

Association of Water Treaters (AWT)

PACE Chemicals Ltd is a water treatment company that believes in providing their customers with more than they expect

Contact PACE Chemicals LTD for water treatment and building energy solutions