FAQs, WATER & GEOTHERMAL BOREHOLES & IRRIGATION

This is in three sections, Water Boreholes, and scrolling lower down, Geothermal Boreholes and Heat Pumps, lower down still, Irrigation. The introductory (italics) sections are for general information, you can skip them if you wish.

WATER BOREHOLES

INTRODUCTION

Water is continually moving through the environment - we call this the water cycle. Water evaporates from the oceans, condenses into clouds and then falls on the land surface as rain, only to flow into rivers and back into the sea. However, there is one aspect of the water cycle that is often forgotten - groundwater. Rainfall doesn't only reach rivers by running off over the land surface.

Most of the rainfall will soak into the soil, which acts like a giant sponge. In the soil some of the water will be taken up by plants and, through a process called transpiration, will return to the atmosphere, but some will soak further into the ground - a process called infiltration - and trickle downwards into the rocks, becoming groundwater. The level at which the rock becomes saturated is called the water table. Water in this saturated zone will flow from where it has infiltrated to a point of discharge. This might be a spring, a river or the sea. Much of the flow of a river will be made up of discharging groundwater, and groundwater provides a vital role supporting wetlands and stream flows.

Water is present almost everywhere underground, but some geological formations are impermeable - meaning that water can hardly flow through them - and some are permeable - they contain fine holes that allow water to flow. Permeable formations that contain groundwater are known as aquifers. The holes that water flows through can be spaces between individual grains in a rock like sandstone, or they can be networks of fine cracks. Very occasionally groundwater will flow in underground rivers, but this is the exception rather than the rule.

Tips on how you can help protect groundwater

You can help to protect the nation's groundwater resources in a number of ways. For example, by conserving water. This will mean less groundwater needs to be pumped, ensuring resources are available for periods of drought and to help sustain ecosystems that rely on groundwater during summer months, such as rivers and wetlands. Also, by being careful how you dispose of chemicals at home. This will help avoid pollution of groundwater which can have a serious impact on the environment and on the cost of providing water to your house. Another way you can help avoid groundwater pollution is by ensuring that your heating oil tanks at home are regularly checked for leaks.

Here are some tips:

  • Look at ways that you can conserve water around the house - don't leave taps running, buy water efficient appliances and fix dripping taps.
  • Conserve water in the garden. Install a water butt to collect rainwater. Reduce water loss by applying a mulch to flower beds, and by watering plants in the evening when less evaporation occurs.
  • In many areas garden fertilizer and pesticides can get into groundwater. Always follow manufacturer's instructions when using garden chemicals, and think about using natural alternatives for pest control.
  • Dispose of unwanted chemicals, used engine oil and similar materials at a properly licensed Public Amenity waste tip.
  • Ensure your home heating oil tanks meet the regulations.
  • Inform the local office of your environment regulator if you are aware of any illegal polluting activities.
  • Recycle! Recycling paper, plastics and metals can be good for groundwater, as recycling cuts the demand for water in industry.

Frequently asked questions, water boreholes.

1) Q. Can anybody have a water borehole?
A. Almost everybody with a garden, or some free external area, can.

2) Q. Do you dowse for water?
A. No, we use the help of the British Geological Survey. They provide a scientific, usually accurate prognosis of groundwater depth. i.e. How deep we have to drill. (see links)

3) Q. Do you guarantee to find water?
A. No, No reputable company will do this. This is a natural and not always predictable, resource. However, the BGS surveys have proven to be reliable. In the unlikely event that we do not find water on your site, we will charge you only for the drilling time.

4) Q. Do I need a licence or permission?
A. No, Anyone is allowed to extract up to 20 000 litres per day without licence or charge. If you wish to extract more than this, you will have to get an Abstraction Licence from the Environment Agency. (see links). We are in contact with the Environment Agency. We are not aware of any plan to change these provisions.

5) Q. Is it bad for the environment?
A. No, the water that comes from your tap has most probably come from one of your water company's boreholes. We abide by government guidelines.

6) Q. Is groundwater always safe to drink?
A. Usually, but not always. It may have dissolved minerals giving it an unpleasant taste, or, in rare cases be contaminated by external sources.

We will always recommend that water intended for drinking be tested by our UKAS accredited laboratory. (your local council will also test the water for you on an ongoing regular basis)

7) Q. Do you give long term guarantees for the quality of the drinking water?
A. No, there is a good reason for this. In the long run you, the end user, are in charge.

We will recommend to you that the borehole water is immediately and extensively tested at our UKAS accredited laboratory (see page on this site). This will allow us to offer you the optimum filtration/purification package for your borehole.

Should you not wish to go to the expense of the tests (several hundred pounds), we will provide you with a standard granulated carbon/UV unit filtration package that will be correctly dimensioned for your water flow requirements. This will be completely adequate in 99.9% of all applications. It is up to you.

We recommend that you have the water tested at regular intervals e.g. annually, to ensure that, however unlikely, no external groundwater contamination factor has arisen. Use us, or your local council (low cost, even free alternative. Ask for the Environment Officer). However, this is again, up to you.

8) Q. Can you deal with excessive mineral content or contamination?
A. Almost always, yes. Our experts will recommend the appropriate filtration/purification equipment to you.

To avoid external contamination you should be careful to locate your water borehole site away from, and uphill of, any possible contaminant source, e.g. Cesspit, open drainage etc.

9) Q. Is a borehole expensive?
A. We are extremely competitive. The costs will depend on many factors, Depth, Geology, Access for our equipment. Not least upon your requirements regarding storage, outlets, filtration etc.

You should reckon on at least £5000 for a quality borehole with a minimum of ancillary equipment, i.e. Grundfos pump and automatic controls, HDPE underground wellhead enclosure with access cover, outlet(s). etc.

10) Q. How long will it take?
A. Usually 5-8 weeks from the date of your first enquiry. This assumes that you request a survey from the BGS (recommended!), this will take 3-4 weeks. We will then send you a written quote within 1-2 days. Assuming that you respond quickly to our quote, both parties will sign a clear agreement setting out our obligations to you. We will order the pumping equipment, which is usually in stock. We then spend a week or so on your site (depending on drilling depth and ancillary equipment you require).

11) Q. We haven't got good access, can you get your machine into the garden?
A. Probably yes, we have different drill rigs for different types of borehole. Usually we will need 1.6m free width for access, however, we have had situations where we have stripped down the drill and rebuilt it!. Call us to explain the limitations and we will tell you if it can be done.

12) Q. Does it make a mess?
A. It can, however we have developed (and imported!) sophisticated systems to keep it as clean as possible. If we are drilling in a sensitive environment we will make sure that every effort is made to keep the site clean.

13) Q. Will the noise disturb the neighbours?
A. Not usually, it is surprisingly quiet and unobtrusive but we all have "those neighbours"!

14) Q. Are the pumps and materials installed guaranteed?, what about maintenance?
A. We use only industry leading Grundfos pumps and Rainbird irrigation components, They are of course covered by the manufacturers guarantee.

Use of the best components means that our installations are very low maintenance. However, we are only a telephone call away!. (see also Maintenance Schedule page).

15) Q. Does it look unsightly when it's finished?
A. The wellhead will all be hidden beneath a metal cover, in a custom designed enclosure, under the ground, out of sight. You can even turf it over or lay a patio on it.

16) Q. What components do you use?
A. We use the acknowledged industry leading equipment for each borehole function.

17) Q. Should some mishap occur, are you insured?
A. Yes,

EMPLOYERS LIABILITY: £10 000 000

PUBLIC/PRODUCTS LIABILITY: £5 000 000

18) Q. How can I find my grid reference for the BGS survey?
A. Go to: http://getamap.ordnancesurvey.co.uk/getamap/frames.htm

19) Q. What guarantees of quality and workmanship do you give?
A. Our workmanship is guaranteed for 2 years. All the components we use are the best we can find. They come with manufacturers guarantees which we pass on to you, the customer.

GEOTHERMAL BOREHOLES & HEAT PUMPS, (GSHP)

INTRODUCTION

(If you are familiar with heat pump principles you can skip this.)

Although we may not know it heat pumps are very familiar to us - fridges and air conditioners are two examples. Ground source heat pumps (GSHP) transfer heat from the ground into a building to provide space heating and, in some cases, to pre-heat domestic hot water.

For every unit of electricity used to pump the heat, 3-4 units of heat are produced. As well as ground source heat pumps, air source and water source heat pumps are also available.

How does it work?

There are three important elements to a GSHP:

1) The ground loop. This is comprised of lengths of pipe buried in the ground, either in a borehole or a horizontal trench. The pipe is usually a closed circuit and is filled with a mixture of water and antifreeze, which is pumped round the pipe absorbing heat from the ground.The circulation pump is usually located within the GSHP.


2) A heat pump.This has three main parts:

  • the evaporator - (e.g. the squiggly thing in the cold part of your fridge) takes the heat from the water in the ground loop;
  • the compressor - (this is what makes the noise in a fridge) moves the refrigerant round the heat pump and compresses the gaseous refrigerant to the temperature needed for the heat distribution circuit;
  • the condenser - (the hot part at the back of your fridge) gives up heat to a hot water tank which feeds the distribution system.
3) Heat distribution system. Consisting of under floor heating or radiators for space heating and in some cases water storage for hot water supply. Again the circulation pump is usually located within the GSHP


What options are available?

The ground loop can be:

  1. a borehole or several boreholes;
  2. a straight horizontal trench which costs less than a borehole, but needs more land area and may ruin your lawn/gardens! within the trench is spiral horizontal (or 'slinky coil') - which needs a trench of about 10m length to provide about 1kW of heating load.

How much does it cost?

Installation

A typical 8-12kW system costs £7,000-£18,000 plus the price of connection to the distribution system. This can vary with property and location.

Running costs

The efficiency of a GSHP system is measured by the coefficient of performance (CoP). This is the ratio of units of heat output for each unit of electricity used to drive the compressor and pump for the ground loop. Typical CoPs range from 3 to 4 although some systems may produce a higher CoP. The higher end of this range is for under-floor heating, because it works at a lower temperature (30-35ºC) than radiators. If grid electricity is used for the compressor and pump, then you should consult a range of energy suppliers to benefit from the lowest running costs, for example by choosing an economy 7 or economy 10 tariff.

Ground source heat pumps and your home

What to keep in mind when considering a ground source heat pump.

  • The type of heat distribution system. GSHPs can be combined with radiators but under-floor heating is better as it works at a lower temperature.
  • Is there space available for a trench or borehole to accommodate a ground loop?, think car parking spaces for boreholes, tennis court spaces for trenches
  • Is the ground suitable for digging a trench or borehole?Dry sand/gravel is the worst conductor, wet saturated stone the best.
  • What fuel is being replaced? If it's electricity, oil, LPG or any other conventional fossil fuel the payback will be more favourable. Heat pumps are a good option where gas is unavailable.
  • Want to be 100% renewable? Buy green electricity, or install solar PV or some other form of renewable electricity generating system to power the compressor and pump.
  • Need a back-up heating system?
  • Do you want the heat pump to supply your hot water?
  • Is there also a cooling requirement?
  • Is the system for a new building development? Combining the installation with other building works can reduce costs.
  • Can you incorporate insulation measures? Wall, floor and loft insulation will lower your heat demand.

Frequently asked questions, geothermal boreholes.

a) Q. Do you decide on the depth of the geothermal boreholes?

A. No, If we are just drilling the boreholes, this is the job of your GSHP (Ground Source Heat Pump) supplier/installer. We will follow his recommendations.

Yes, In the case that we are responsible for the complete GSHP installation with boreholes. We will consult with the GSHP manufacturer. Using a BGS Geological Survey we will take the ground conductivity characteristics into account. We will then recommend a borehole configuration to the client. This recommendation is backed up by our system dimensioning guarantee

b) Q. Why should I not take advantage of the package that the Heat Pump company offers?

A. In many cases this will be fine. Beware of mass market suppliers who will take every opportunity to save cost at the expense of long term reliability. Also, some heat pump suppliers take a hefty mark-up on drilling services which they hire in.

The cost of the borehole and installed loops is very probably the single largest cost item in the heat pump installation. It therefore pays to come direct to us.

A small example.

The best quality high thermal conductivity Bentonite grout (see below), costs £10-£15 per 25Kg bag. A single typical geothermal borehole will require several dozen bags. Some borehole suppliers then choose to use building plaster mix...

We use high conductivity Bentonite grout:-

PHYSICAL SPECIFICATIONS

  • Thermal Conductivity (TC) Range 1.73 - 2.01 Wm-1K-1
  • Permeability1 <6.9 x 10-8 cm/s
  • Percent Solids (based on TC) 65.1 - 70.4 %
  • Grout Weight (based on TC) 1.59 - 1.73 kg/litre
  • Linear Shrinkage Potential (based on TC) 40 - <3 %
  • Maximum Particle Size <300 µm
  • Unit Yield Range (based on TC) 131 - 168 litres/unit
c) Do you guarantee your Geothermal Borehole / GSHP installations?

A. Yes we do. Our guarantee is, we believe, the best that you will find in the industry.

We guarantee our borehole installations for 10 years see guarantee

d) Q. Can you recommend a reputable GSHP supplier/installer?

A. Yes we can. We have contact with a few selected suppliers whom we trust to provide high quality service. Please call, or use the email link. We will need your post code to recommend a local installer. (see links on the menu bar below for some reputable GSHP manufacturers/installers)

e) Q. Will it be cheaper to use you to drill the boreholes?

A. Probably, possibly not. What is important is that your heat pump installation gives you many, many years of trouble free operation.
Remember, the above ground "box" is easy to replace. What is deep under your garden is not.
Ask your potential supplier/installer if he will guarantee the life and performance of the underground GSHP loops (see c above) as well as the heat pump itself.
Should you get a cheap offer for drilling and equipping boreholes, think carefully, ask a lot of questions regarding methods and materials quality. Should you take the offer, be on site to watch the work being done.

f) Q. Will you drill geothermal boreholes for heat pump companies and use their materials or loops?

A. No, this is where some of the larger companies offering the heat pump "package" choose to save money. Should the loop supplied leak when we pressure test it on site, it costs time and money to rectify the situation. Somebody has to pay the extra cost. We prefer to avoid this problem.

g) Q. I wish to have a heat pump/boreholes retrofitted to my house which has access problems, can you do this?

A. We have a very compact, but powerful drill requiring only 1.6m access width, so we can usually find a place to drill. (See equipment/gallery for photos).

h) Q. 'How many boreholes do I need for my installation?'

A. Here is a very approximate way to find out (Please do however, consult your heat pump supplier before making any decisions!)
Sizing of boreholes for a given Ground Source Heat Pump (GSHP) performance.
The use of borehole collectors for GSHPs is necessary when there is insufficient ground area, or limitations on the use of existing ground areas e.g. valuable gardens etc.

Vertical heat collectors usually operate at a higher efficiency, i.e. produce a higher heat yield per metre, than horizontal collectors. They are however, usually more expensive to install than horizontal collectors.

Vertical, i.e. borehole, collectors can provide between 25 and 65 watts per metre of active collector. This figure depends upon the thermal conductivity of the strata in which the borehole is drilled.
This is one of the reasons that we ask for a geological (BGS) survey of the proposed site. They will give a, usually reliable, projection for this value where you are. Relying on assumptions for this figure, can turn out to be expensive if your new heat pump installation fails to deliver the performance that you expected (and payed for!).

The term active collector is used to denote that part of the geothermal probe which is in direct contact with the ground source, i.e. the high thermal conductivity grout filling in the borehole.

The following calculation can be employed using an average value of 40W/m


Heat Pump capacity in KW 10KW (Heating, average family 3-4 bed house with reasonable insulation)

Energy provided by ground source 7KW (7000W)

Energy yield per metre of active collector 40 W

Collector length required is therefore 7000/40 = 175 metres

(This can be one borehole of 175 metres or two boreholes of approximately 90m, (the most usual solution), or three boreholes of slightly less than 60m, should there be e.g. hard rock below this depth.

i) Q. Can I get financial assistance, i.e. a grant to help fund the installation of a GSHP system?

A. Yes you can, up to £1200 from the BERR Low Carbon Buildings Programme.


IRRIGATION

Q. Why should I choose your company rather than one of the many other irrigation companies?

A. The roots of our company lie in waterwell drilling and storage. It was for us a natural step to go one stage further into irrigation. We have a team leader and designer with almost 30 years experience in installing all sizes of irrigation systems.

Should you wish to have a water borehole to supply your irrigation system, we are perhaps the only UK company that can offer a hydraulic rotary drilling service coupled with high quality water storage and irrigation installations, all from one partner.

We have also invested in the latest trenchless pipe laying equipment and use the highest quality components (usually Rain Bird)

Above all, we offer a value for money, fixed price service, we do not quibble.

Q. Will an automatic sprinkler system use more water than I am currently using?

A. No. -- In fact, it may actually save you water. A well designed, efficient irrigation system applies exactly the amount of water needed by your garden. You will not have to worry about wasted water if you forget to turn off the hose. Additionally, with a rain shut off sensor your system will know when it is raining and simply turn itself off when not needed.

Q. Does having a sprinkler system really save me time?

A. Yes. You won't have to spend time watering the lawn. It will do all the watering for you - even when you are away from home!

Q. Can having a borehole / irrigation system really save me money?

A. Yes. Particularly if your supply is metered. Yes also, if you wish to protect valuable lawns and plants from the increasingly hot and dry UK summers.

Q. Will automatic sprinklers water as well as I do when I water by hand?

A. An automatic sprinkler system will do a more efficient job because it will be designed based on your garden's watering requirements, using specific products designed to water grass, trees, shrubs or garden plants according to individual need.

Q. We generally get a lot of rain. Do we really need a sprinkler system?

A. If it rained every three days -- the same exact amount each time -- you probably would not need a sprinkler system. But nature doesn't work that way, and the only way to ensure a healthy garden is to make certain that your lawn and plants receive a regularly timed and evenly measured amount of water. In the summer when there is little rain, your plants can suffer damage after just a few days without water.

Q. What are the components of an automatic sprinkler system?

A. A typical installation comprises of a controller (which functions as the brain), valves (which open and close to release and stop the flow of water to underground pipes) and sprinklers (which distribute water to specific areas). The sprinkler network can be further automated with rain shut off devices, soil moisture sensors and drip irrigation zones.
If you already have an existing garden design you might need to move plants, trees or shrubs in order to install the system. Make sure you have prepared the area well before you begin the installation.

Synergy uses professional Rain Bird components to ensure reliability, longevity and function.

(7 of the 10 World Cup pitches in South Africa were fitted with Rain Bird irrigation systems!)

Q. How much will a good sprinkler system cost?


A. The price depends upon many factors such as property size, type, landscaping, number of zones etc.

Q. Will I have difficulty operating the controls?

A. Synergy offers a wide selection of the most advanced sprinkler timers and controllers that are flexible enough to meet your watering needs, while being simple to program and adjust.