Mechanical Installations Blog

renewable energy cyprus

The Guide to Home Geothermal Energy

Efficient and economical, geothermal heats, cools and cuts fossil fuel use at home. Whether you’re in sunny Florida, or snowy New Hampshire, a ground-fed climate system can free a consumer from fluctuating energy prices and save money on power bills immediately. Here’s how it works.

Drill and Fill: Installers thread pipe into a hole a few inches wide and over 100 feet deep. As wind and solar hog the alt-energy spotlight, this technology has remained underground.

“You’re not making heat, you’re moving heat,” Colorado geothermal installer Jim Lynch says. Installations like Lynch’s tap into the earth below the frost line–which always stays around 50 degrees Fahrenheit–to reduce a home’s heating and cooling loads. All HVAC systems require energy-intensive heat movement, a task responsible for over half of the average house’s total energy demand. Geothermal works more efficiently because the system’s mild starting point creates an efficient shortcut to the target temperature. Imagine a 100-degree Florida day or a 0-degree Michigan night: Spot the system 50 degrees, and it doesn’t work so hard to get the house comfortable.

Unlike wind and solar, geothermal’s power source never varies.

Bob Brown, vice president of engineering with equipment maker Water­Furnace, says, “The ground’s there all the time. It’s great for heating and it’s great for cooling. All I’ve got to do is bury a plastic pipe, put fluid in and, lo and behold, I’ve got a great system.”

HOW GEOTHERMAL HAPPENS

* In the ground: A water-filled, closed loop of 1-inch high-density polyethylene (HDPE) pipe ferries heat between the earth and the house. Pipes descend 4- to 6-inch-diameter vertical wells–the number and depth depend on the house’s site and size–before ganging together in a header and bringing lukewarm water in through the basement walls. Drillers backfill each hole with bentonite grout (or new enhanced grouts, engineered with fly ash) to maximize thermal conductivity.

* In the house: Pumps cycle water through the pipe loop to the heart of the system: the geothermal unit, which acts as furnace and air conditioner. This machine uses refrigerant and the temperate water from the underground pipes to heat or cool air. The air is then circulated through standard ductwork. With a device called a desuperheater, the unit uses excess heat to warm up domestic hot water at no added cost. The results feel the same as those from any standard forced-air HVAC system.

THE FLOW

Air in the ducts (1), refrigerant in the geothermal unit (2), and water in pipes (3) flow past each other like interlocking gears. Water brought from underground transfers heat to the refrigerant, or absorbs heat from it, depending on the season. Like an air conditioner, the unit compresses or expands the refrigerant to raise or lower its temperature. Finally, the refrigerant, now heated to 180 F or chilled to 40 F, fills condenser/evaporator coils. Air in the ducts blows across the coils to be cooled or warmed, then flows through the house.

THE SUPPLIES

* The bit: This mud-drilling bit grinds soft earth and funnels it back into hollow, 20-foot drill-shank sections. Corkscrew auger bits, in contrast, pound through solid rock. A new mud bit spinning at 1000 rpm, pushing downward with between 300 and 500 pounds of pressure, is good for five 150-foot holes.

* The pipe:
Water-filled HDPE pipes absorb heat through their walls. This sawed-off cross-section shows two pipes fused in a butt joint made by pressing the molten edges together at over 500 F. The joint, stronger than the walls of the pipe itself, resists rust, rot and leaks for a purported 200-year life span.

* The unit:
A combined furnace and air conditioner, the geothermal unit manages all-season climate control from the basement. Using the same principles as a refrigerator, which removes heat from food, this machine and the buried pipe remove heat from the earth or from the house. Wired to a 50-amp circuit, it works without venting, combustion or risk of carbon-monoxide poisoning.

THE SETUP

Vertical coils (1) fuel a system by using less total HDPE pipe than horizontal coils (2), in which loops of pipe fill shallow trenches exposed to constant heat just below the frost line. In pond systems (3), a blanket of water insulates coils anchored on racks. Hard ground can inhibit deep digging, stopping Colorado installers like Jim Lynch from doing simple vertical work: “Texas, Nebraska–that’s some easy drilling down there,” Lynch says. His clients receive options 2 and 3. If an existing system gets a geothermal upgrade, it may operate as geothermal 90 percent of the time, while the old boiler or furnace fires up only on the coldest days of the year. The payback period on retrofits averages 12 to 15 years; on new installations, it can get as low as three to six.

MONEY SAVED

A typical 2000-square-foot home in Commack, N.Y., was recently retrofitted with a geothermal system. Tax credits, the inefficiency of the existing system and a low-interest loan combined to create immediate savings. The monthly payment is now $24 lower than the old monthly HVAC expense.

Installation cost: $30,000 — $11,000 (tax credit) = $19,000

Annual costs: $3945 (old system) — $2076 (geo) = $1869 saved

Payback period: $19,000 / $1869 = 10.17 years

Monthly fuel costs for old system: $329

Monthly geothermal costs: $173 (power) + $132 (loan) = $305

GEOTHERMAL MISCONCEPTIONS

1. It’s a geyser. Hot springs and other steamy subterranean liquids are not related to residential geothermal. Those are unusual local seismic circumstances. Home systems work everywhere.

2. The water table is in the way.
Installers drill straight through it. On Long Island, where the water table is just a few feet below the surface, saturated sand makes for some of the best drilling and most efficient heat transfer possible.

3. It generates electricity.
Industrial-scale geothermal power plants can generate electricity. Home systems don’t–but they do save electricity (or fuel) by replacing conventional home heating and cooling with more efficient equipment.

Via Popular Mechanics

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Geothermal energy

A geothermal energy  cooling / heating system is based on using the full potential of the constant temperature and thermal conductivity of the earths substructure.

We can see this phenomenon in basement areas where during the summer the area is cool and during the winter warm without the use of air conditioning.

Geothermal energy can be broken down into two categories :Open loop systems and closed loop systems.

Open loop geothermal energy for cooling / heating is the pumping of under ground water source through a Heat pump (or VRV) and the return of the water after the energy transfer. This method needs a constant water supply.

geothermal systems cyprus

Closed loop Geothermal energy systems can be divide into two categories.

Horizontal closed loop Geothermal energy system is installed at least 1.5 meters below the ground with pipe spacing of at least 1.8 – 2.2  Rm per m². Output is 20 – 35W/m². This system has the disadvantage of requiring a large area to be installed.

geothermal systems cyprus

Vertical closed loop Geothermal energy system where the loop is installed in a vertical bore well (6” – 8” diameter) and 60 – 120 deep. The minimum distance between the wells is 5 meters and the output is 40-70W/meter of depth, and depending on the soil structure. This system is more popular as you need less space and have a higher output.

geothermal systems cyprusThe heat which is collected from the earth is transferred to the  system(Heat pump, CHILLER, VRV e.t.c.) and the exchange is made via heat exchangers and transferred to the cooling circuit of the unit as in a normal system. Due to the fact that the temperature is constant in the earth (±18.5°C) the energy required for this  this process is much less than in a normal system where the  air temperature is 40°C in summer and 5-10°C in winter.

Geothermal  energy can be used for under floor heating, fan coils, or for VRV systems, and the savings in comparison to a normal Air to water system can be up to 50-60% depending on the application and use of system.     

   

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photovoltaic systems cyprus

Photovoltaics

Photovoltaics is a term which covers the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry.

A typical photovoltaic system employs solar panels, each comprising a number of solar cells which generate electrical power. PV installations may be ground-mounted, rooftop mounted or wall mounted. The mount may be fixed, or use a solar tracker to follow the sun.

Solar PV has specific advantages as an energy source, its operation generates no pollution and no greenhouse gas emissions once installed, it shows simple scalability in respect of power needs and silicon has large availability in the Earth’s crust.

PV systems have the major disadvantage that the power output is dependent on direct sunlight, so about 10-25% is lost if a tracking system is not used, since the cell will not be directly facing the sun at all times. Dust, clouds, and other things in the atmosphere also diminish the power output. Another main issue is the concentration of the production in the hours corresponding to main insolation, which don’t usually match the peaks in demand in human activity. Unless current societal patterns of consumption and electrical networks mutually adjust to this scenario, electricity still needs to be stored for later use or made up by other power sources, usually hydrocarbon.

Photovoltaic systems have long been used in specialized applications, and standalone and grid-connected PV systems have been in use since the 1990s.They were first mass-produced in 2000, when German environmentalists and the Eurosolar organization got government funding for a ten thousand roof program.

Advances in technology and increased manufacturing scale have in any case reduced the cost, increased the reliability, and increased the efficiency of photovoltaic installations. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity, have supported solar PV installations in many countries.More than 100 countries now use solar PV.

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The power of Net Metering in your home!



One of the frustrations of off-grid systems is that the extra energy in the summer months can’t be stored for the winter.  Batteries typically store energy for only 3-5 days.  When the batteries are full there is no way to store the extra energy.  With net metering, you are feeding back your power over the summer and you get credited for it in the winter. Annual net metering rolls over a net kilowatt credit to the next month, allowing solar power that was produced in July to be used in December.

It encourages consumers to play an active role in alternative energy production, which both protects the environment and helps preserve natural energy resources. A net metering system gives you the advantages of producing your own clean renewable energy without concern maintenance hassles and with very durable components which has long life.

Net metering also allows small systems to result in zero annual net cost to the consumer provided that the consumer is able to shift demand loads to a lower price time, such as by chilling water at a low cost time for later use in air conditioning.

Image result for net metering

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We’re Hiring – Ζητείται Μηχανολόγος Μηχανικός

Η εταιρεία Z&X Mechanical Installations στη Πάφο ζητά άμεσα να εργοδοτήσει υπεύθηνο εργοτάξιου για τις μηχανολογικές εγκαταστάσεις σε ξενοδοχείο υπο ανέγερση. 

Απαραίτητες οι γνώσεις και εκπαίδευση στον τομέα Μηχανολόγου Μηχανικού καθώς επίσης και προϋπηρεσία 5 χρόνια.

Τρόπος υποβολής αιτήσεων
Οι υποψήφιοι θα πρέπει να αποστείλουν ηλεκτρονικά το βιογραφικό τους στην ηλεκτρονική διεύθυνση sales@zandxgroup.com

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mechanical installations cyprus

WASTE WATER TREATMENT FOR DOMESTIC USE

SCOPE

The information below outlines the options available for disposal of domestic wastewater in lieu of a sewer connection and looks briefly at the management implications.

In absence on any specific data on the house, its occupancy and use, site, soil conditions, adjacent water features, adjacent boreholes, local environmental authority requirements; the information below provides only basic details to identify the potential options for wastewater disposal and is not intended to be definitive.

All dimensions, volumes and distances are those that would be required in the UK, local requirements may be different, and should be determined by an appointed MEP engineer.

 

1.   WASTE WATER TREATMENT OPTIONS

1.1.  Septic tank

A septic tank is typically a two chambered, buried tank with an effluent outlet to a drainage field. The septic tank, usually made of concrete, is designed to be watertight. The principle of operation of a septic tank is that wastewater enters the tank first, where heavy solids sink to the bottom and grease and oils float to the top. The effluent passes from the first chamber to a second chamber, by gravity, where further settlement occurs. Most solids entering the septic tank settle to the bottom and are partially decomposed by anaerobic bacteria to form sludge. The effluent then passes in to a soakaway or a drainage field, where the majority of the treatment occurs. There should be no direct effluent discharge to watercourses.

A properly maintained septic tank keeps solids and grease from entering and clogging the drainfield, the land into which the tank overflows drain. To be effective, the soil must be suitable and undergo permeability tests, the result of which may be required to be submitted to the local environmental authority as part of the consent to discharge application. If the soil is not suitable, then the ground can become waterlogged and give rise to issues of odour.

Generally for a four person dwelling the septic tank would be of a minimum 2.7 m3 litres capacity, additional occupants would require the tank capacity to be increased by 180 litres per person. They need to be emptied on a regular basis, at least once per year. American case studies show tank capacity ranges from 4 m3 for a three bedroom single-family house, up to 15 m3.

 

1.2.  Packaged Treatment Tank

Typically these are off the shelf plant, sized to match the expected effluent load and simply require installation and commissioning. Typical examples of packaged treatment plant are defined below.

Rotating Biological Contactor (RBC)

These are usually a single unit comprising of 3 chambers, the first stage being the primary settlement tank where the solids are settled out and retained as sludge.  The partially treated effluent passes first to the anoxic and then the aerobic stage, where the secondary treatment occurs.

RBC’s generally protrude above ground and are therefore, visually intrusive. They require a power supply, although the motor is generally small as the speed required is between 2 and 4 rpm (revolutions per minute).

An RBC can tolerate some fluctuations in hydraulic and organic load but can suffer if there is a shock load. RBCs have no scope for adaption should the building change, i.e. if the wastewater flows are increased. The increase in flow will have to be accommodated within the plant or a new plant will be needed.

Overall, RBC’s are a simple and stable treatment process that has been proven over the years but are not ideally suited for single dwellings due to the relatively low flows they may receive.

Activated Sludge

An activated sludge plant uses the injection of air in to the wastewater to breakdown the organic load. The plant can be either two or three chambered units and with the air being bubbled up through the effluent from an aerator in the base. The process generates slurry which settles in the based and sludge is formed containing active microbes. Some of the sludge is re-circulated back in to the unit and retreated, keeping the units biomass active. The quality of the effluent can be very high and can provide some nutrient removal, such as nitrates. Similar to RBC’s, they can accept some load variations but not sudden shock loads.

Generally activated sludge plants are wholly buried and only the top is visible, so are therefore, visually unobtrusive. However, the air blower does need a surface mounted fan, which can give rise to aesthetic and noise issues. They do use more power than an RBC.

A variation of the activated sludge treatment is the sequencing batch reactor (SBR). The treatment occurs in a single chamber, where the blower is alternates between on and off, to allow the settling out of the sludge.

Packaged treatment plant general comments

There are many types of packaged treatment plant available, all of which perform better with a constant flow of effluent, ensuring that the final effluent is treated to the correct standard. The local environmental authority may require the effluent quality to be monitored, to ensure the consent standard is not contravened.

In general, packaged plant are reliable and will, if maintained, provide years of service. They work best when there is a constant flow. If large variations in flow are expected, then precautionary measures, such as an additional balancing tank are required, to ensure the flow is kept at a constant rate.

Most types of packaged treatment plant hare the same following features:

  • Off the shelf products but need careful selection to ensure the discharge consent will be met.
  • Relatively compact and easy quick to install
  • Easily maintained, by reputable manufacturers/installers who can offer maintenance contracts
  • Relatively unobtrusive, as they are predominantly installed below ground
  • Can achieve good quality effluent discharge and the effluent can be discharged direct in to a watercourse, if the correct discharge standard is met
  • Relatively inexpensive.

However, they do have some disadvantages:

  • They are not a do it yourself (DIY) item and do need specialist maintenance
  • As they have mechanical and electrical components, they do wear out in time and will need replacement
  • They do need de-sludging which, depending on the plant can be between 6 months and 2 years, depending on the plant and usage
  • They require a power supply
  • Will not provide any treatment in the event of a power outage or mechanical breakdown
  • Can generate noise and occasionally odour problems.

1.3.  Reed Beds

Vertical Flow Reed Beds

These work on a similar principal to traditional filter beds, where the effluent is spread over the top of the reed bed and allowed to pass vertically down through the filter media, generally gravel and sand as well as the rhizomes of the planting, to the outfall point. Organic matter can settle on the surface, which can give rise to some odour issues.

High levels of treatment are possible and so can be used to for secondary treatment, following a primary settlement tank such as a septic tank, but are generally used as tertiary treatment.

The effluent flow in to the reed bed can occur under gravity, providing there is sufficient hydraulic head, generally around 1.5 m from inlet to outlet, hence they do not necessarily require power.

They are easy to maintain as failure tends to be gradual and as such, preventative and remedial action can be carried out well in advance of total failure.

Visually, they can be very attractive and can provide a wildlife habitat.

Generally they require between 2 and 5 m² of land per person and can be quite expensive to install and can be sensitive to shock loads.

A        Existing septic tank

B        Pumping station (if required)

C       Vertical reed-bed

D       Pumping station

E        Vertical flow reed-bed

F        Humus Tank

G       Balancing tank

H       Horizontal reed-bed

J        Flow control chamber

Horizontal Flow Reed Beds

Unlike the vertical flow reed bed, the flow occurs horizontally through the filter media. The air flow through the filter media is limited and so strong effluent can be poorly treated and potentially aerobic conditions can occur, giving rise to odour issues.

Similar to vertical flow reed beds, they are generally seen as a tertiary form of treatment but can be used for secondary treatment, following a septic tank. They require more land take than a vertical flow reed bed, between 5 and 10 m² per person, secondary treatment.

Although many consider that they are suitable for secondary treatment, there some who would suggest that they are really only suitable for tertiary treatment. Therefore, there is some confusion on their suitability.

Visually, they can be attractive and natural looking, be able to accommodate a wide range of plants. They can be cost effective, if installed as a DIY item, but again, the design needs to be considered very carefully.

As the flow is horizontal through the media, the media can become blocked and therefore needs careful maintenance. Normally, with good pre-treatment, the bed can be used for up to 10 years before the media and planting requires replacing and replanting.

General comment about reed beds

The main consideration for reed beds is the land available to accommodate them and do need regular maintenance, i.e. the reeds need to be harvested regularly and the waste material needs to be disposed of carefully, as the reeds accumulate toxins.

Also, the local MEP planners should consider the risk of freezing of the reed beds in case of very low temperatures.

1.4.  Cess Pools

Cess pools are large sealed underground tanks where sewage is stored. The capacity of the cess pool below the inlet drain must be a minimum of 18,000 litres for 2 persons and must be increased by 6,800 litres for each additional user.

They need emptying on a regular basis, as they cannot be allowed to exceed their capacity. Generally, cess pools should be avoided, except where no other option is viable.

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GROUND SOURCE HEAT PUMPS




Ground source heating/cooling utilises heat pump technology. A heat pump is a device that moves heat energy from one place to another and from a lower to a higher temperature, or visa versa. Heat pumps are available as both heating only or reverse cycle heating/cooling systems and are classified according to the type of heat source and the heat distribution medium used.

There are many different variations of ground source energy systems available, but the main types involve utilising the natural thermal conditions of the ground, large bodies of underground water, or large bodies of surface water. Ground source heat pump systems (GSHP) can be used for heating or cooling purposes and obtain their thermal energy from the ground, which has a much more stable temperature profile throughout the year. For heating, the system pump-extract the heat from the underground and distributes it through a pipe system. For cooling, the process works in the opposite way, extracting heat from the building and injecting it into the ground.



heat pumps



A GSHP system contains three main components:

1) The ground side to get heat out of or into the ground.

2) The heat pump to convert that heat to a suitable temperature level.

3) The building side transferring the heat or cold into the rooms.



heat pumps



The system is a process which allows the transport of heat from a lower temperature level to a higher one, by using external energy. The thermodynamic principle behind a compression heat pump is the fact that a gas becomes warmer when it is compressed into a smaller volume. In a heat pump, a medium with low boiling point (“refrigerant”) is evaporated by the ground heat, the resulting vapour (gas) is compressed (by using external energy, typically electric power) and thus heated, and then the hot gas can supply its heat to the heating system. Still being in the high pressure part, the vapour now condenses again to a liquid after the heat has been transferred. Finally, the fluid enters back into the low-pressure part through an expansion valve, gets very cold and can be evaporated again to continue the cycle.



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cooling systems

THERMAL STORAGE FOR COOLING PURPOSES

Cooling storage using water, ice or other phase change materials is widely used in countries where summertime cooling requirements are high.

1.   ADVANTAGES

The greatest benefit of this system is delivered to buildings which have relatively low nighttime compared to their daytime peaks. Additional benefit may be gained through the use of electricity to generate cooling on potentially lower cost off-peak tariffs. The advantages in a well-designed and operated system can include:

  • Reduced installed chiller and heat rejection capacity;
  • Decoupling of cooling demand from production allowing the opportunity to use lower energy tariffs;
  • Possibility to use lower night time ambient temperatures for heat rejection giving improved COPs and energy performance;
  • Potential to more easily operate variable flow systems due to the buffering effect reducing rapid changes in operation; and
  • The non-instantaneous nature of cooling production can give higher reliability than reliance on the chiller operation. 

In order to fully optimize the system’s capital investment and operating costs of the cooling equipment and infrastructure the correct sizing of the equipment is critical.

2.   DESIGN RECOMMENDATIONS

When designing the cooling systems to be utilised, the profiles of the required cooling load are key. The demands placed on plant over periods of 24 hours and weekly are required in conjunction with the peak values for the design of the cooling accumulator systems. This is to ensure that the total cooling loads are accounted for during the whole storage cycle which may extend beyond the commonly used 24 hour period. The cooling storage system must be designed carefully to be able to meet the extended loads over time as well as peak demands.

 

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natural ventilation

NATURAL VENTILATION


Natural ventilation systems are intended to provide sufficient outside air to achieve appropriate standards of air quality and to provide cooling when needed. Since the cooling capacity of natural ventilation is limited, a key design challenge is to limit heat gains through good solar control and careful management of the internal gains. Naturally ventilated buildings do not aim to achieve constant environmental conditions, but take advantage of dynamics to provide comfortable, controllable conditions for the occupants

Natural ventilation systems need to be designed to achieve two key aspects of environmental performance:

  • Ventilation to maintain adequate levels of indoor air quality
  • In combination with other measures, ventilation can reduce the tendency for buildings to overheat, particularly in summer


natural ventilation

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mechanical installations

ARISTO PEARL PARK RESIDENCES

( A)

A solar system is installed to provide domestic hot water .The  Solar system uses all the available solar energy and at times when it’s not enough an electric element.

The solar system consists of  2 Solar panels 1.5×1.0  & a 200 Litre  Hot water cylinder.

 

( B)

A multi split system is installed for the space air conditioning and heating of the villa. The system consists of  air cooled  Outdoor units and  Indoor units ( Wall type) . The benefits of the air cooled Multi system from the spit unit type air conditioning is the efficiency and less number of outdoor units and the ability to install the outdoor units much longer distance from the indoors .

 

( C)

A complete plumbing system is installed consisting of : ( a)  Central pipes using Pex-C pipe in pipe piping and manifolds for the piping of all the sanitary fittings for both the hot and cold water as well as the drinking water through out the project.  ( b ) A complete sewage system consists of all the pvc plastic piping for all the sanitary fittings to the first outside manhole. ( c ) Connection of all the sanitary fittings to the plumbing and sewage piping and installation of all the accessories. ( d ) 1 pressure pump system per apartment  to provide high water pressure to all the sanitary fittings,

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