The Cooling System at Ramat Hanadiv

Within the structure of The Visitors Pavilion, you will notice a variety of options for energy conservation that minimize the impact on the environment. The geothermic system installed in the building is the first attempt in Israel to adopt this method for cooling interior spaces. The first geothermic system was built in 1912, and only began to gain momentum around the world in the 1960s and 1970s. Today, large-scale public projects and private homes are adopting this system.

What is a Geothermic System?

A geothermic system uses the ground temperature, which maintains relative heat stability throughout the year. No matter if there is freezing snow or a heatwave, the ground heat that is below the three upper meters remains constant – at 17-23 degrees, depending on its location on the face of the Earth. Water is an excellent heat exchanger. A closed circuit water pipe carries heat from the building into the relatively cold ground, cools down the water which then returns cool so it can extract additional heat energy from the building. In cold locations overseas, this system is used as a heating system in the winter.
There are actually two separate water systems that carry the heat. One system flows in the ground, reaches a heat chiller and returns to the ground. The second water system conducts the cooled water into the building and returns with more heated water to the chiller.

The water’s role in the geothermic water chiller is identical to the role of the fans in an air conditioner’s heat chiller: to cool the compressor’s gas condensation pipes which heat up when compressing the gas in order to cool the water that flows to the building. The gas that is compressed into the pipe is what cools the water that flows to the building.
The pipe that conducts the water in the ground can be buried in two ways: vertically into the depth of the soil (as is done at Ramat Hanadiv) and horizontally. When laid horizontally, care must be taken to ensure that the pipes do not damage the construction of other infrastructure in the vicinity.

How is the System at Ramat Hanadiv Constructed?
The temperature of the ground at Ramat Hanadiv is a pleasant 21.7 degrees. In the area under the “Footprint Garden,” 21 cylinders were excavated with a diameter of 15 centimeters and at a depth of 30 meters. The cooling engineer’s recommendation was to drill 60 meters; however, after drilling 30 meters, the drills reached a very hard layer of rock and there was concern that by drilling into the hard layer, the flow of the spring in the area of Ramat Hanadiv (Ein Tzur) would be damaged. This is one example of the types of environmental considerations that must be addressed as it relates to the system. We do not discount one ecological consideration in favor of another, rather we try to reconcile both issues together.

In each cylinder, a regular PEX water pipe is inserted down to the “belly” of the earth and then rises up again like a loop. When hot water enters the cylinder, it transfers heat to the soil and the water is cooler than when it entered. The water continues to flow to the heat chiller, in which a temperature exchange between the two water systems occurs – the system above ground and the one below ground.
Water from the above ground water system exits the chiller and enters the building and goes to the various air conditioning units. Each interior space at the Visitor Pavilion has its own air treatment unit (ATU), operated only when in use. Cold water from the chiller enters the unit and flows to the radiator. The fan sucks the cold from the radiator’s duct and brings it inside the room through a tin duct.
Ramat Hanadiv’s geothermic system is only used for cooling. The regular air conditioning system is operated at the Visitors Pavilion, which hosts thousands of visitors each year, only when necessary as backup for the geothermic cooling system.

The advantages of the geothermic cooling systems over the conventional air conditioning system are:

1. Conservation of electricity: Maintaining the temperature of the condensation pipes is achieved through the geothermic cooling by the flow of

the water, as opposed to cooling the condensation pipes in a regular air conditioning system which is executed by electricity-guzzling fans. There is a 25% savings of electricity consumption in the cost of cooling.
2.    Conservation of storage space: The heat chiller unit of the geothermic system is one-tenth the size of the heat chiller in a regular air conditioning unit.
3.    Flexibility in terms of the installation location: Because the geothermic chiller does not require fans and does not emit air, it can be stored in any place including closed spaces
(for example, under the stairs inside a house).
4.    Preventing noise pollution: The geothermic system’s chiller does not generate noise pollution as does a conventional air conditioning system because the cooling takes place underground and not inside the chiller.

5. Preventing the emission of heat into the atmosphere: The geothermic cooling system buries the heat that comes from the building in the ground, while an air conditioning system expels the heat into the atmosphere which is already hot. It is more efficient and cost effective to expel the heat into a cold place than to expel hot energy into a hot place. The low energy consumption reduces the emission of greenhouse gases from the power stations into the atmosphere.
6. Avoiding peak consumption periods: Because the ground temperature remains constant at all times, there are no consumption peaks. A conventional air conditioning system’s electricity consumption is based on the temperature outdoors; the hotter it is outside the more energy is invested in compressing the heat into the atmosphere.
7. Protecting nature by minimizing environmental problems: like acid rain, air pollution and thinning of the ozone layer.
8. Minimal maintenance: Maintenance of the geothermic system is one fourth that of a regular air conditioning system.

Additional Projects:
In the Palestinian Authority: The city of Ramallah received a donation from the European Union to build a green building. 15 shafts that are 150 meters deep were drilled into the ground in order to meet the building’s cooling needs. The drilling of the geothermic cooling shafts is unique because their narrow diameter and great depth require special drills. The insertion of pipes also requires great skill so the shaft’s walls will not collapse after the drills are removed and filled with silt. This type of drilling is conducted by a company in the Authority that specializes in this field. It is a pity that the building does not provide data on its energy consumption.

Other Places in the World:
The entire Olympic Village in China, U.S. army bases from the 1990s and also in Europe, all U.S. schools, and in the past year – 85 thousand installations in Europe and 200 thousand installations in China.
It is notable that the environmental friendliness of the geothermic system, which is expressed in the conservation of electrical consumption and minimization of the impact on the environment, is enhanced by the following additions:
1.    A rooftop garden that serves as a layer of insulation for the Visitors Pavilion and offers shade.
2.    Stone cladding on the walls using a semi-dry method which leaves air between the structure and the cladding that creates an addition layer of insulation.
3.    Upper windows which let in day light save the cost of operating lighting fixtures that heat up interior spaces.
Green construction principles have been implemented at the Ramat Hanadiv Visitors Pavilion with close and cautious supervision throughout the process. Ramat Hanadiv has achieved a level of excellence based on the criteria of Green Construction Standard 5281 of the Ministry of Environmental Protectionת the Israel Standards Institution and the U.S. standard LEED. The geothermic system is only one of many examples of this excellence.

System Engineer: Yehoshafat Aharoni, Asa Aharoni Engineers and Consultants Ltd.

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