Challenges with Ground Source Precooling

One of the main changes from mainstream geothermal use in the technology that we plan to use at HCC are the temperatures that we are trying to reach for the interior of the Precooling area.

Geothermal or ground source heat pumps are typically used to condition room air for the comfort of its inhabitants. This temperature is always near 70 degrees. In order to bring a crop to a ideal temperature for storage the room temperature of the precooling area needs to be much less then 70 degrees.

There are several things that will contribute to the interior temperature of the Precooling area before it is conditioned.  The walls must also be super insulated to maintain the temperatures we are trying to reach. The crop that is brought into the area will be at the exterior temperature. Large quantities of product will certainly add to the load for the cooling equipment. This temperature will be near 80 degrees or higher for most of the crops that are harvested in the summer months.

Bringing large quantities of 80 degree crop to 40 degrees demands quite a lot from the cooling equipment.

If the gray building is the Precooling Room we are much better to draw temperature change from the ground temperature than from the air temperature.
The high air temperature (80)during harvest time for most WNC crops would certainly be more costly to cool than the constant ground temperature(57).

History of Geothermal Energy

Geothermal Technologies are not new...

The challenges of making geothermal a mainstream technology center around education. The technology is a guaranteed energy reduction if installed correctly. The challenge lies in educating prospective clients and contractors in its use. This is one of the things that we are focusing on at Haywood Community College. We will give the public answers to the questions that they ask. We can teach probable contractors what they need to know.
Look how far we've come.

Date	Event
Pre-history	Use of caves’ geothermal energy for winter warmth and summer cooling; people gathering at hot springs to enjoy warmth from deeper geothermal resources.
Early history	The Romans used geothermally heated water in their bathhouses for centuries. The Romans also used the water to treat illnesses and heat homes. In Iceland and New Zealand, many people cooked their food using geothermal heat. Some North American native tribes also used geothermal vents for both comfort heat and cooking temperatures. Most of these early uses of the Earth's heat were through the exploitation of geothermal vents. Early peoples also utilize near-constant subsurface temperatures (geothermal energy) to keep vegetables in root cellars from freezing or spoiling.
1860s	Energy from hot springs begins to be used in the United States to heat homes and bathhouses.
1886	Hot water from the Banff, Alberta, hot springs piped to hotels and spas.
1904	Italian scientist Piero Ginori Conti invents the first geothermal electric power plant.
1946	First ground-source geothermal heat pump installed at Commonwealth Building in Portland, Oregon.
1960	Pacific Gas and Electric begins operation of first large-scale geothermal power plant at the Geysers north of San Francisco, producing 11 megawatts. Today, 69 geothermal generating facilities are in operation at 18 resource sites around the United States.
1970s	During the oil crisis of 1973, many countries begin exploring alternative sources of energy, including geothermal energy. This sparks government-sponsored renewable energy research programs in Germany, Sweden, Canada, the United Kingdom and the United States. Geothermal heat pumps and underground thermal energy storage systems gain popularity as a means to reduce heating and cooling costs, especially in commercial and institutional buildings.
1975	Drilling begins to assess high-temperature geothermal resources for electricity generation in British Columbia.
1976-1986	Ten-year federal research program assesses geothermal energy resources, technologies and opportunities for Canada.
1990s	As public concerns about environmental issues such as air pollution and climate change grow, governments in Canada and elsewhere take a greater interest in using renewable energy as a way to decrease greenhouse gases and other emissions.
1990	Ontario Hydro funds a program to install geothermal heat pumps in 6,749 residences not served by natural gas.
2004	Western GeoPower Corp. applies for government approvals to build a $340-million, 100-megawatt geothermal power plant at Meager Creek, northwest of Whistler, B.C., which could begin producing power as early as 2007. Manitoba government announces program to provide loans of to $15,000 towards installation of geothermal heat pump systems.

What WNC Crop?

Here is what we know to date:

For those of you who are experts in this area forgive me if you are reading:

Crops that use Precooling in WNC, or Postharvest Precooling Methods

Apples
Berries
Peppers
Cabbage
Broccoli
Onions
Blueberries
Green Beans
Field peas
Tomatoes

Methods of Precooling, We can use forced air, hydrocooling, or still air. Each of these methods is different and applies to different crops. For example: Apples respond well to hydrocooling but tomatoes need room cooling. Tomatoes are very sensitive to chilling. A geothermal unit can assist in each of these areas because it simple allows the owner to bring a the temperature of the cooling fluid, air or water in this case to a temperature needed by the commodity  (crop). Each crop needs a different temperature but the temperature change needed of the cooling fluid will always be less when using geothermal. This temperature difference is referred to as the DELTA T. Delta T from 58 to 50 requires less energy than Delta T from 82 to 50. The temperature of the earth is constant (for the most part) at depths fro 50 to 200 feet. We utilize this in any type of ground source heat pump.

The challenge at this point is to create equipment that will accomplish this precooling in a method that is cost effective and accessible to people in WNC. We are currently using ground source heat pumps for residences and commercial buildings but people prefer to be at 70 degrees and tomatoes like it more near 40-50 degrees depending on their maturity. This being one of the challenges of the progress,

Today's link in the industry:
A picture and bio of the MT Research Station.

http://www.ncagr.gov/research/mrs.htm

What is Precooling?

Precooling is the rapid removal of heat from freshly harvested crop.

Dr. Chris Gunter has provided a wealth of information in the area of Pre Cooling crops.

 

Check out the following link for some of the basics on precoolers:  http://pre-coolers.net/vertical.html

 

 

 

 

 

Progress goals to date:

April May and June of 2013 offer the following objectives for the grant:

Advertise and hire a part-time consultant/subject matter expert to assist with the project development.

John Mark Roberts (HCC Building Construction Lead Instructor) completes NCSU geothermal training.

Partner with commercial geothermal heat pump manufacturer, professionals and other educational providers established.

Identification of pilot vegetable crop for the demonstration, finalize building/trailer and location of demonstration unit confirmed.

Create working drawings of the demonstration unit.  Create bids on building or installation work.

Geothermal Training Report

John Mark Roberts did attend training in on May the 21st through the 25.
He attended the International Ground Source Heat Pump Association Headquarters in Stillwater Oklahoma

TVA Ag and Foresty Fund, NC Department of Agriculture & Consumer Services

The purpose of this blog is to inform and report on the progress of a Work Project At Haywood Community College in Western NC.

We have received funds to accomplish the following things:

1.  Develop a demonstration vegetable pre-cooling unit based on geothermal cooling.

2.  Document the cost saving of geothermal cooling to traditional methods of pre-cooling.

3.  Create a professional workforce development program on geothermal cooling in general for residences and agricultural applications.

4.  Create an educational unit on geothermal heating and cooling within a Heating Ventilation and Air Conditioning (HVAC) curriculum certificate.