Home Automation , Building Management eHouse – GHE use of free energy for recovery of soil .
The ground heat exchanger is well-known component of the ventilation system and recuperation .
It is based on place deep underground (at least 2m) in the form of heat exchanger tubes with large diameter (eg 200mm) or gravel deposits . The idea of ground heat exchanger work involves the use of energy of the earth to the air cooling for mechanical ventilation in summer (several – a few degrees), and heating it to the same value in the winter.
Clean air passing through the ground heat exchanger uses the energy of the ground reducing expenditures for additional heating and cooling of the air , despite the assurance of forced mechanical ventilation providing fresh air from the outside .
This air is heated (in winter) in two or more steps before blowing the premises:
- ground to pass through a heat exchanger causes its temperature rises by up to several degrees , during heavy frosts ( – 20st) rarely falls below 0C, GHE output and almost does not depend on the outside temperature .
- Initial , additional heating air or water wells, solar panels for the next few to several degrees before entering the recuperator
- heating the heat exchanger in the recuperator .
In recuperator heat exchanger can be of any type (cross , rotary , Push-pull) .
It works on the principle of pure heat and cold air from the outside through the dirty and hot exhaust air from the house . - Heating the air to the required value electric heater or water heater before serving home air .
Depending on the type of the recuperator on the output of the heater is Control Automation , which reheats the air to clear the preset room temperature – Air flow to the premises . - Additional outdoor water heater for leaving recuperator – using the heating vent (blow)
Taking into account the installation of ground heat exchanger once we decide on mechanical ventilation or recuperation .
GHE type should also think about taking into consideration not only the cost but also the characteristics of each .
Heat Pipe
Requires a long (over 50m) pipes buried at a depth of at least 2 meters .
The pipe must be laid with a fall to ensure the possibility of dew condensation to one place (in the manhole air intake).
This water must be periodically manually or automatically removed.
To perform such a heat exchanger in some cases it is necessary to perform very large earth-moving excavator digging up a large part of the plot .
For houses with cellars can be considered, the foundation laying pipes around the basement (at least one meter away from it) which significantly reduce earthworks and dug a large portion of the plot .
Note that the ground unless it is concentrated will settle very slowly and unevenly , leaving a trace for years.
Some manufacturers of ground heat exchanger pipe sell ready-pipe systems with an extra antifungal , sanitation, etc. .
Additionally reportedly have better heat transfer characteristics between the air and the surface of the pipe .
However, they are much more expensive than standard pipes of the same diameter , which results in very frequent use of alternatives.
In the case of a tubular heat exchanger must also be taken into account that , it is not possible to clean the pipe and wash several dozen in one piece , located a few meters below ground .
In this context, it is difficult to determine what happened and will happen and how it will look in a few or several years .
It is also difficult to determine whether or not it becomes a habitat for fungi , mold , diseases and allergies in the future .
The efficiency of the ground heat exchanger of this type depends primarily on the depth of the foundation tube , its length, , type of soil and the ground water level .
Ground Heat Exchanger and gravel filter
Another option is ground heat exchanger so-called gravel filter.
It consists in the fact that we make a big deep down in the soil sealing and isolating him from the land of the native film.
Throw tons of the gravel (in volume to 10m3), the air passing through it prior to entering the recuperator heats itself.
To perform this method GHE , need a low level of ground water throughout the year , substantially below the bottom of GHE.
Gravel filters also equipped with sprinklers to allow periodic flushing of gravel deposits .
This filter does not require digging the whole plot and can be installed on a much smaller area .
The problem with gravel filters is the need of its regeneration (work at half-time) .
This involves two of the same filters and switching them every few hours .
As in the case of tubular heat exchangers, it is possible to produce a mushroom , mold , lichens and allergens in beds of gravel .
In the case of gravel filter is theoretically possible replacement deposits of gravel , But it is a very expensive operation and rather unprofitable in houses .
Such solutions are practiced in hospitals and sanatoria , where there are additional requirements for sanitation and these filters have a special design to enable and simplify the exchange of the gravel deck .
Advantages and disadvantages of ground heat exchangers:
- free energy recovery in winter (heating) and summer (cooling)
- high cost of installation
- large amount of earthwork
- virtually no possibility of cleaning and maintenance
- the possibility of development of fungi , mold , GHE allergens in the environment
- the need to use Automation GHE management for effective and appear to work by Control dampers , assistive devices , Control heating – eHouse Home Automation
- recuperator prevent pressure drop to normal operation because the vacuum is produced at home (effective exhaust is stronger than supply) . GHE Causing the need for additional fans supporting and electricity consumption loss final efficiency.
To effectively use the GHE is necessary to optimally control the operation of the GHE home automation – control heating and recuperation part of the system eHouse – Home Automation Producer and Home Automation .
An alternative to the GHE in some plots , can be well chilled in summer and warming in winter .