513 MWh yearly: Small vertical turbines can use ‘waste HVAC energy’ to generate power

The ability of heating, ventilation, and air conditioning (HVAC) systems to produce clean electrical energy was investigated in a recent study.

Researchers at the Distance University of Madrid in Spain investigated the possibility of efficiently utilizing the airflows generated by these extensively used systems as a man-made wind resource.

The team decided on a vertical wind turbine generator after examining the wind flow pattern because of its small size, light weight, and nominal power of 9 kW, which makes it perfect for installation on HVAC systems.

Results showed that the concept, tested at a data center in Colombia, can produce about 468 MWh per year from a single location.

Harnessing artificial wind

It’s critical to first determine which airflows are appropriate for producing electricity from artificial wind flows. Air from moving ships at sea, railroads, and HVAC systems—all of which provide constant airflow—are a few examples.

To assess the energy potential of these flows, data collecting is essential, with a particular emphasis on wind direction and speed. These variables are measured over time by weather stations and anemometers to assess wind conditions. The viability of the airflow is evaluated with the aid of statistical analysis, which includes average wind speed and distribution.

Selecting the proper wind turbine is also essential, taking into account factors like weight, noise levels, durability, and type (vertical or horizontal). The power curve of the turbine and the frequency distribution of wind speed are used to compute the energy production, accounting for the number of operating hours per year.

The case study examines a data center in Colombia. It features three Liebert HPC-M chillers, each equipped with eight EC-FAN fans. These fans, operating at 480 V and 900 rpm, provide constant vertical airflow to cool the facility’s computer equipment.

Two chillers run continuously, while the third is on standby and rotates weekly. The fans, with 900 mm blades and 2.4 kW power, expel heat to maintain ideal operating temperatures, ensuring efficient 24/7 data center operations.

According to researchers, a variety of horizontal and vertical-axis small wind turbines exist, but the consistent wind direction observed from the chiller’s equipment, coupled with environmental turbulence, leads to the choice of a vertical-axis wind turbine .

The compact size and lightweight design of the “Tesup V7,” which has a nominal output of 9 kW, led to its selection. Six turbines that are mounted atop the chillers and use clamps for simple installation may produce a combined 513.82 MWh annually, with each turbine having an annual output of 85.64 MWh.

Sustainable energy

The study shows that with two chillers continuously operating, the system is equivalent to six wind turbines generating 513.82 MWh.

The 16 fans of the chillers, consuming a total of 336.39 MWh annually, generate a net electricity of 467.6 MWh after accounting for a 9 percent loss due to unplanned downtime and maintenance.

Researchers claim that this 131.2 MWh surplus can be used to feed renewable energy sources into the electrical grid or used to fulfill other electrical needs within the data center, hence improving sustainability.

The economic research estimates that the initial cost of nine micro wind turbines, installation, and related equipment will come to $1,23,101 (€111,540). These turbines have an estimated useful life of 20 years, with an annual maintenance cost of $1,109 (€1,005), projected to increase by 12 percent.

The cash flow starts to show a positive trend in the third year, which suggests good returns. Economic viability is demonstrated by the anticipated net present value at year 20 of $8,02,010 (€726,686) and an Internal Rate of Return of 50.69 percent.

Additionally, the installation prevents approximately 300.12 tons of emissions, contributing to climate change mitigation and promoting a sustainable energy future.

The details of the team’s research were published in the journal Nature.