How to have a perfect climatisation in a house of 200 square meters at a price of 500 watts/hour in summer

Mr. Daniel Ciupila, expert in climate solutions, shows us how we can cool in summer, presenting the features and benefits of the system Passive Climate.

What is Passive Climate?

The passive cooling system is generally used at low outdoor temperatures. A passive cooling system is based on a heat exchanger combined with radiant heating and cooling system. As heat exchangers for ground can be used horizontal collectors, vertical collectors or spiral-type collectors.

How does it work?

Water from wells or boreholes is transported through a heat exchanger that is cooled constant to 13-15°C, from this exchange it is transported by the radiant system and ventiloconvectors.

The result is the passive cooling without requiring a heat pump type machine. For the system operation will appear costs only for functioning of circulation pumps. The length and the diameter of the collector loops depend on the power needed that has to be covered. This information will be given by a specialist designer. Due to the complexity of the installation it is required to contact a designer.

A proper planning is absolutely necessary and a detailed thermal simulation for a long term of the ground.
The passive cooling systems are generally used because they are capable of cooling at very low cost (natural cooling). These types of systems can be easily mounted.

The methods of source extraction for Passive Climate are:

The deep drillings with probes – the most constant method by point of view of fluctuations in temperature – between 10 and 14°C in summer, depending on soil composition, temperature remain fixed once the system was installed. For example, for a house of 200 square meters, we need 240 ml of drilling with vertical wells in U form. This cost is given by two recirculation pumps with a total consumption of maximum 500 watts/hour.

Ground water from a depth greater than 30 m – we get between 8 and 12°C, depending on the area. In this situation, the drillings must ensure the required flow of heated or cooled surface and not to remain without water for various reasons. For example, for a house of 200 sq. m we need 3.5 – 4 mc/h. Here the consumption is greater than 1.2 kW maximum, given by a submersible pump and a circulation pump but the investment is lower.

The systems that running with Passive Climate:

1. Ventiloconvectors – in case if you do not take into account criteria such as aesthetics, noise, air currents, the ventiloconvectors are great for this system. The inlet temperature on flow is from the source thermal controlled depending on the energy calculation for climate.

2. Underfloor cooling, ceiling or wall – it is the aesthetics and efficiency, it does not imply any other air currents and energy costs.

a. Cooling ceiling – it is the most efficient in terms of yield that it sends, 60-65 w/sq.m at a humidity of 60%, it is sold in the form of panels of drywall or it is mounted on the ceiling pipes of 9.9 mm covered with plaster. The departure temperature on flow is over 15°C in order to avoid the dew point, at a lower temperature it is required a dew point control. Usually the flow starts with 16°C and is come back with 19°C.

b. Wall cooling – it is obtained 40- 45 w/sq.m at a humidity of 60%, it is mounted in pipes of 9.9 mm in wall and it is covered with plaster. It works with the same temperatures mentioned above.

c. Underfloor cooling – it can only be used on limestone surfaces, where it obtains 30- 35 w/sq.m at a humidity of 60%, with temperature of the above heating agent.

In conclusion, such a system for a house of 200 square meters can be used in the warm season with the lowest cost of operation and in cold weather with a heat pump with a cost of electricity bill around of 500 lei/month for 6 winter months. Thus we have a system that does not depend on gas prices, the cost and approvals for gas or wood boilers, so we have maximum comfort at a minimum price.

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