Thermal Energy Storage at Alamo Colleges 

Alamo Colleges is thinking ahead and optimizing its energy use with its new thermal energy storage tanks.

Check out this informational website prepared by our team of summer interns.

What is the purpose of a thermal storage tank?

A thermal storage tank allows us to produce thermal energy, such as chilled or hot water, during periods of low electrical demand.

By producing thermal energy when electricity demand is low ("off-peak"), Alamo Colleges can reduce its energy usage during high-demand hours ("peak hours"). This process helps Alamo Colleges balance energy demand between daytime and nighttime and can save money because utilities often charge a lower rate for electricity used during off-peak hours.

It also helps CPS Energy maintain the grid by reducing the amount of energy needed when energy use in San Antonio is high.

How it works?

Thermal energy storage is the process of cooling water during off-peak hours and then using it in connected buildings during peak hours. This is a daily cycle that alternates between day and night.

During the day, at peak hours, cold water already stored in the thermal tanks circulates cool air throughout the connected buildings. This process is called the discharge cycle. While chilled water is drawn from the tank, the water inside absorbs sunlight and heats up. This warm water will need to be cooled again.

At the end of a peak cycle, the thermal tank is full of warm water, which is sent to a chiller to cool before the next peak cycle. This process, called the off-peak or charging cycle, occurs at night when the building is not in use, and no cool air is needed. The chiller moves the cold water back into the thermal storage tank, preparing it for the next peak cycle.

Once the tanks are ready for the following day, one complete thermal energy storage cycle is finished.

Saving money and serving the community

QuickFacts:

• Demand Response is a CPS Energy strategy to reduce peak power usage during high-demand periods in order to stabilize the electrical grid
  
  
• Alamo Colleges has participated in demand response since Summer 2013
  
  
• Alamo Colleges earned $103,000 in 2013 through participation in the program hand as doubled the performance rebate by 2025

Why Demand Response?

Hot summers are CPS Energy's highest electricity demand times, or "peak periods". When we power on our A/Cs, more power plants are powered up, too. This is expensive, raising electricity prices for everyone. 

If the demand is too high, even expensive energy may not produce enough electricity for the community, leading to brownouts and blackouts.

Instead of firing up more power plants, CPS contracts Alamo Colleges to reduce electricity use during these periods, and Alamo Colleges is paid what would have gone to peak power plants, via rebates.

Other participants include Joint Base San Antonio-Lackland, San Antonio Water System, Matheson-Trigas, and Supa Doors. Together, we reduce our electricity demand by 1300KW during peak times--the equivalent of taking 650 houses off the grid at once!   

What is Demand Response?

CPS Energy's Demand Response season spans from June 1st to September 30th. CPS Energy can call on Alamo Colleges a maximum of 25 times, totaling a maximum of 75 hours, to substantially reduce our energy use for any number of hours between 1 p.m. and 7 p.m. Alamo Colleges is given a minimum 2-hour advanced notice for a demand response event. 

Alamo Colleges begins to reduce the amount of energy it is using by an agreed-upon amount. Our HVAC (air conditioning) systems are throttled down to lower settings (NEVER turned off) to reduce it's energy use. 

Starting in 2015, we switched from real-time cooling at our chiller plant during high-demand periods, to drawing from our thermal storage tanks which were pre-cooled the night before (also see thermal storage on this page).

Reference the CPS Energy website for more information on demand response in San Antonio.

How Can I Help?

If you notice the room warming, turn off unnecessary appliances (lab computers, unattended lights, overhead projectors, idling copiers/printers), and close the blinds on sunny windows. Keep the outside doors closed to minimize outdoor air infiltration. 

All appliances produce heat which can make a difference when our HVAC system is throttled down during an event. Additionally, employees are welcome to use desk fans and to take advantage of our summer casual dress to keep cool.

Note: Buildings should never become unreasonably hot or stuffy. If this happens in your study or work area, please notify facilities as soon as possible.

Recycling at Alamo Colleges

Recycling is an easy way to reduce your waste. At Alamo Colleges we are taking initiative to make sure we make recycling an option across our campuses.  

Every year millions of trees are cut down to make paper products and billions of pounds of plastic pollution enter our oceans. When we recycle, we prevent reusable material from ending up in our landfills and oceans. Recycling can help reduce pollution, and save natural resources and energy because it allows us to make new products from old materials! For instance, it takes 95% less energy to create an aluminum can from recycled aluminum than it would with new aluminum. 

Frequently Asked Questions about Recycling

How Do I Recycle?

• Put your recyclables in the blue recycling bins located next to the trashcans.

What Can I Recycle in These Bins?

What cannot be recycled in the blue containers?

• Light bulbs, batteries, ceramic dishes, pots & pans, glassware, plastic cups, styrofoam, paper plates & napkins

What should I do with paper containing sensitive information or non-public information (NPI)?

• Alamo Colleges has a strict NPI policy that requires such material to be disposed of accordingly. Any sensitive or papers containing NPI should be shredded and put into the regular trash bin.

Do I have to separate my recyclables?

No, everything can go in the same bin.

What about containers with solid food?

• Recyclables should not have food on them. If a container can not be washed out, continue to put it in the regular trash bin.

Where can I request an additional recycling bin?

• You can direct your question and concerns to your campus hotline.

Where can I learn more about recycling in San Antonio?

• Try logging onto our contracted company's webpage

Northwest Vista and Northeast Lakeview Colleges use recycled water for irrigation, and in their cooling towers.

There are four types of water to know about:

• Domestic water is the filtered and chlorinated water we get in all of our taps at home. This water is a finite resource that is pumped out of the Edward's Aquifer.
  
  
• Grey water often goes straight down the drain, but it is safe to reuse, for example, in irrigation and to fill toilet bowls.
  
  
• Black water is unsafe for reuse, so it always goes down the drain to be treated for pathogens and bacteria.
  
  
• Purple is the industry color label for "treated wastewater effluent", or recycled water. Alamo Colleges receives recycled water piped directly from SAWS (San Antonio Water System). This water goes through extensive filtration and cleaning processes, but nutrients can stay in the water.

As an extra precaution, the water is NOT used for drinking or indoor use, it is used:

• for grounds irrigation
• for NVC's air conditioning cooling towers
• to fill the NVC lake

Solar power is a promising renewable energy source in San Antonio. It can help us power our buildings and keep our lights on, while reducing our dependence on harmful fossil fuels like coal.

How does it work? 

The Sun emits light in the form of photons. These photons travel at the speed of light to reach Earth, which takes about 8 minutes.

Upon arrival, the photons are absorbed by solar cell panels made of semiconductor materials that are placed in areas that receive a significant amount of sunlight, like our rooftops.

The technology used in these panels allow us to harness the Sun's energy and make it usable. When the photons hit the panels, their cells free energetic electrons, creating a flow of energy, or electricity.

This electricity then travels through out electric grid to our buildings and homes.

3 Reasons Alamo Colleges incorporates solar generation as a source of energy:  

1. We're being responsible! 
   • It is a clean alternative to other fuels; that does not generate harmful emissions like fossil fuels that negatively impact our atmosphere.
   • The panels operate quietly without disrupting the surrounding natural and built environment.   
    
2. We're being smart! 
• The costs of solar has come down substantially within the few years, and in San Antonio there is plenty of free sunshine to use.  
• Once the panels are installed they require little maintenance. 

1. We're being a leader!
• Solar installations are on the rise and the way of the future. Alamo Colleges strives to be a leader and is offering it's students and community an opportunity to learn about solar. 

Did you know?

All Alamo Colleges' academic students can ride the VIA bus for FREE!