Efficient Operation of Swimming Pools and Hydrotherapy Pools

Transcription

1 Efficient Operation of Swimming Pools and Hydrotherapy Pools June 2012

2 Introduction Swimming and hydrotherapy pools located in schools are typically smaller (and may well be much older), than those found in a typical leisure centre. They may also be located outdoors. Having a pool can increase a school s energy costs by 25 to 40% and yet those responsible for their operation and maintenance may not necessarily be specialists in pool management. This guide therefore aims to provide school managers with the means to manage their pools energy use, by providing easily implemented, practical advice. The process involves five basic steps: Step 1: Make someone responsible for managing the energy use of your pool Step 2: Understand the configuration of your pool and its controls Step 3: Manage pool heating and evaporation Step 4: Manage the energy used in ancillary areas Step 5: Monitor on-going performance in order to maintain savings The following sections discuss each of these steps in turn. Although this document is a management guide, which does not focus primarily on technical issues, we have provided some advanced guidance in each section for those who feel confident enough to address more technical issues. To make it easier to follow we have coded the tasks in each step. The green clipboard tasks are the basic requirements. The blue spanner tasks are more advanced opportunities You should try to tackle all the green clipboard tasks (across all steps) first. Contact Energy and carbon management team energy.en@nottscc.gov.uk Tel:

3 TAKING CONTROL OF YOUR POOL STEP 1: Make someone responsible for managing the energy use of your pool STEP 2: Understand the configuration of your pool and its controls STEP 3: Manage pool heating and evaporation STEP 5: Manage the energy used in ancillary areas STEP 5: Monitor ongoing performance in order to maintain savings Task 1: Nominate members of staff to the role of Pool Energy Manager Task 1: Make a simple plan of your pool systems Task 1: Check the pool water temperature Task 1: Check the heating systems in changing rooms etc Task 1: Record, monitor and refine Task 2: Gather cost and consumption data for your pool Task 2: Check pool hall air temperature Task 2: Check lighting is being used appropriately Task 3: Define pool usage requirements Task 3:Check pool hall humidity Task 4: Use pool covers Basic Requirements More Advanced Opportunities Task 4: Create a pool log book Task 5: Check that ventilation rates reduce when pool covers are used Task 3: Check the amount of hot water being generated for showers Task 4: Ensure general maintenance tasks are completed Task 5: Consider the potential for refurbishments 2

4 STEP 1: Make someone responsible for managing the energy use of your pool Task 1: Nominate members of staff to the role of Pool Energy Manager The key responsibilities for the Pool Energy Manager are: To identify the current cost of your pool s energy use To create and maintain a schedule of your school s pool usage requirements To confirm whether or not the operation of your pool matches your requirements To put in place (with appropriate technical support, if necessary), the remedial steps required to improve control of your school s pool While the detailed adjustment of modern pool controls can require a high level of technical skill, the management of your school s pool should not be viewed as a technical activity. It may be that your Site Manager or Caretaker is the ideal candidate for the role of Pool Energy Manager, but it is advisable not to just allocate sole responsibility here. For example, some schools have appointed a member of their teaching staff, bursar, or business manager to assist or take overall responsibility for the role, usually because they have a particular interest in financial control, environmental or sustainability issues. The important point to recognise is that the role requires a manager, not a technician and it will usually be better for two or more people to work together, so that knowledge is not lost if the responsible person leaves. Many of the tasks involved in managing your pool (for example, measuring space temperatures), can link readily into curricular activities and it can be helpful to have a Pool Energy Manager who can recognise and promote these opportunities to the whole school. 3

5 STEP 2: Understand the configuration of your pool and its controls Task 1: Make a simple plan of your pool systems The first task for your newly appointed Pool Energy Manager should be to get a basic understanding of the energy facilities associated with your pool. The Pool Energy Manager will need to understand: Where the boilers are that heat your pool s water. How the ventilation of the pool hall is provided (unless you have an outdoor pool!) Whether there are any pool covers. This information can often best be captured by marking up a school site plan to show the locations of this equipment. If you can, it is also useful to identify and mark-up the location of significant control devices such as time switches and room thermostats/sensors (although this is not essential at this stage). Task 2: Gather together cost and consumption data The Pool Energy Manager should also collect together cost and consumption data for electricity and heating fuel use in order to gain an understanding of the value at stake and to create a baseline against which subsequent performance can be assessed. Obtaining this information will be easier (and more accurate), if your pool s energy supplies are separately sub-metered. If you have separate meters for your pool supplies, get into the habit of recording monthly consumption figures. If you do not have separate meters for your pool energy supplies, then you can estimate typical energy costs using the simple procedures in Calculator 2.2, at the end of this guide. Recording regular monthly readings of the school s electricity and gas meters will help you to check the accuracy of this estimate. Accurate data collection will lead to early identification of savings opportunities. Refer to Calculator 2.2 for calculation of approximate pool energy costs 4

6 Task 3: Define pool usage requirements Next, establish when your pool is used. You will need to determine: Who uses the pool during the school day and when; Who uses the pool outside the school day and when, for example after-school clubs or community use; Who the first and last people are who access the pool every day Which weeks of the year the pool is used. (Is it used during school holidays? Does community use continue? Is it a seasonal pool/outdoor pool?) It is important to understand the usage, as this will enable you to ensure that time controls are set appropriately. It will also indicate who should be made responsible for shut down procedures and to determine who needs to be informed of best practice in using the pool facilities. Also, if the pool is being used for community use, it is useful to understand the energy implications of this so that appropriate re-charging can be considered to cover the additional cost of using the pool for these periods. If you have an outdoor pool which is only used seasonally, you might want to consider the cost of using the pool, compared to the alternative of using other locally available pool facilities. Task 4: Create a pool log book Create a file, containing manufacturers operating and maintenance information for all the energy consuming equipment associated with your pool (this information can often be downloaded free of charge from the manufacturers websites, if you have the model name or number of the equipment concerned). You can also ask your Local Authority contact or maintenance contractor to: Show you how the time switches are adjusted Show you how to check for correct operation if you have advanced controls like a Building Management System Demonstrate adjustment of space temperature controls and explain their function Explain the energy saving features of the controls installed Keep all the information you gather in a pool log-book along with recorded performance data (see later). This will provide you with a ready reference manual which can be used by the Pool Energy Manager to make immediate adjustments to the control of the pool s systems. It should also be used to record system adjustments/performance and should be reviewed each term. 5

7 STEP 3: Manage pool heating and evaporation Task 1: Check the pool water temperature Keeping the pool water heated to the appropriate temperature uses a significant amount of energy, about 32% of the total energy used by a swimming pool. This is shown in the pie-chart below: Effective temperature control is an important issue for schools as, in general, a 1 C rise in pool water temperature increases fuel consumption by around 5%. The following table shows the temperatures recommended for a range of pool use types: Pool usage Recommended Water Temp ( C) Competitive and fitness pool 27 Conventional main pool and adult teaching 28 Children s teaching and leisure pools 29 Special needs 30 For outdoor pools, as heat losses will be higher, it is even more important that the pool water is not overheated. Use a thermometer to check the temperatures actually occurring in the pool at your school. Checks should be carried out and recorded daily, at varying times of the day. Make adjustments, as necessary. Setting the pool water to the correct temperature can lead to significant savings opportunities. Refer to Calculator 3.1 for calculation of the approximate energy cost savings 6

8 Task 2: Check pool hall air temperature If you control the temperature of the air in your pool hall, it should ideally be 1 o C higher than the pool water temperature when the pool is in use. Operating with a pool hall air temperature above or below this optimal value will lead to increased energy costs and potential discomfort for bathers leaving the pool. For each 1 C reduction in the pool hall temperature, schools will save around 5% of the heating fuel used by the pool areas. Refer to Calculator 3.2 for calculation of approximate savings Task 3: Check pool hall humidity Managing the humidity of the air in the pool hall is important as excessive relative humidity (RH) levels, together with the presence of the chemicals from the pool treatment, can create a very corrosive atmosphere which is potentially damaging to the building structure. Against this, operating at low RH levels increases a pool s energy consumption due to the need for increased ventilation or de-humidification. It is therefore important to maintain pool hall humidity conditions within reasonable limits. These are typically 55-65% RH, but may vary depending on the construction of the pool hall. Humidity should be checked on a daily basis, at varying times, using a handheld RH meter. The simplest ventilation systems just remove the moist air from the pool hall and draw in drier, fresh air from outside the building. These systems incur high energy costs due to the need to heat up the large quantities of incoming fresh air to match the pool hall temperature. More sophisticated systems directly control the humidity and reclaim the heat from the extract air before it leaves the building. You may need to speak to your Local Authority contact to understand how your pool s ventilation system works if it is more complex. Allowing humidity to increase by 1% RH reduces ventilation or de-humidification energy use by around 2.5%. Refer to Calculator 3.3 for calculation of appropriate savings. Task 4: Use pool covers A pool cover is used to reduce evaporation from the pool surface, thereby reducing the energy associated with heating the pool water. Pool covers can be used for indoor and outdoor pools. There are two main types of pool covers: Physical pool covers which are sheets of buoyant plastic material, which are floated on the pool surface when it is not in use. Some covers may be motorised, while others will need to be rolled on and off manually. Liquid pool covers are chemicals which are added to the pool water in order to inhibit evaporation from the water surface when it is undisturbed. 7

9 A typical physical pool cover Using a pool cover can save at least 10% of the energy consumption for a typical pool. Carry out the following steps to minimise energy use when the pool is not in use: 1. Use the pool usage requirements established in Step 2 to determine which hours during the week the pool is not in use. 2. If you have a physical pool cover, check that it is currently used and that it is used at all possible times (for example, during the day when the pool is not in use as well as overnight). If your pool cover is not currently being used, investigate why. The use of pool covers is often a significant task at the end and start of each day. Operators may not be aware of the importance in energy saving or in protecting the building. If you use a physical pool cover it is important that the staff responsible for supervising the pool are trained to know what to do if anyone becomes trapped on top of, or underneath, the cover. 3. If you are using a liquid pool cover you should check that the dosage rate of the chemical is in line with the manufacturer s recommendations. 4. Establish formal daily shut down procedures. These should include: Putting the pool cover in place; Adjusting any temperature/ventilation settings if not controlled automatically; Switching off any lights, including in changing rooms. Using a cover can save at least 10% of energy consumption for a typical pool Refer to Calculator 3.4 for calculation of approximate savings Task 5: Check that ventilation rates reduce when pool covers are used While the use of pool covers will reduce the amount of energy needed to keep the pool water warm overnight, this represents only part of the savings that are potentially available. The reduction in evaporation that occurs when pool covers are in place means that less ventilation (or dehumidification), will be required to maintain the required RH levels. In modern systems that automatically control RH, this turn down should occur automatically. In older systems, however, ventilation may continue to be provided at the normal day-time rate leading to unnecessary electrical and heating energy use. In these circumstances it may be possible to manually reduce ventilation rates in the evening or, better still, to retrofit automatic controls. 8

10 STEP 4: Manage the other energy used in ancillary areas Task 1: Check the heating systems in changing rooms etc. Changing rooms and other ancillary areas will be heated. These areas should be checked to ensure that they are maintained at suitable temperatures (around 20 C) during the times that they are in use and that the heating is off at other times. See the Taking Control of your Heating guide for detailed guidance on how to do this. Correctly setting the times and temperatures for the pool hall and changing room heating can save about 6% on the pool s heating fuel. Refer to Calculator 4.1 for calculation of approximate savings Task 2: Check lighting is being used appropriately If possible, the lighting of the pool hall and changing areas should be turned off whenever areas are unoccupied or when there is adequate natural daylight. If there are not automatic lighting controls in place, ensure that the lights are manually switched off whenever possible. If there are blinds to reduce glare in the pool hall ensure that these are not left shut all day. Use natural day light when safe to do so in the pool hall and remember to switch off the other lights. Ensure windows and any skylights are cleaned regularly to allow natural light in. For further guidance see the Practical, Fast Track, Whole School Savings guide with its approach to labelling switches. It should be noted that some forms of lighting (principally sodium and metal halide), are not amenable to frequent switching due to their prolonged start-up times. Fluorescent, LED, tungsten halogen and induction lights all respond well to manual switching however. Ensuring that the pool hall and changing area lighting is switched off whenever possible can save up to 3% of a typical pool s energy Refer to Calculator 4.2 for calculation of approximate savings Task 3: Check the amount of hot water being generated for showers Showers use a considerable amount of hot water, often provided by large storage cylinders. The storage cylinders should be monitored to ensure that they are going cold by the end of the last pool session, as any remaining heated water will just go cold overnight and can be considered wasted energy. This will require the site manager to check the storage tanks after the last pool session if they are still hot, then the water heating hours can be reduced. In all cases, however, ensure that the Legionella control measures advised by your Local Authority are strictly adhered to. Also check that bathers shower before entering the pool to minimise contamination of the pool. Minimising the contamination reduces the amount of cleaning of the pool water that is required (backwashing) and hence reduces energy consumption. 9

11 Task 4: Ensure general maintenance tasks are completed Maintenance is a key part of ensuring energy efficient operation of pools. The following should be checked: Ventilation: Where fans are used, ensure that filters are cleaned regularly and that any dampers are lubricated and operating correctly. Check ductwork to ensure it is free of leaks. Pipework, taps and showers: Ensure pipework, taps and showers are checked regularly for leaks as this wastes both water and heat. Even a slow drip can cause significant energy losses. Insulation: Regularly check the condition of insulation on hot water tanks, pipework and valves and replace if it is damp or damaged. Also ensure that it is put back in place after any maintenance works. Boilers: have gas boilers serviced annually by a reputable firm (or every 6 months if the boilers are oil fired). Motors and pumps: Develop procedures to ensure that any idle motors or pumps are switched off when not in use and ensure that they are kept clean and corrosion free. Lighting: Ensure that light fittings are kept clean to allow maximum light output. Similarly any skylights or windows should be kept clean to allow maximum natural light in. Backwashing: Backwashing refers to the process whereby the flow of the pool water through the filter is reversed to flush out the accumulated dirt in the filter. This can be very energy intensive as energy is used to pump the water used to clean the filters and heated pool water is lost to drain. Although energy can be saved by minimising the quantity of water used in backwashing, take special care to avoid compromising water quality and safety. Ensure that the manufacturer s guidance is followed so that backwashing is not carried out more frequently than is recommended. 10

12 Task 5: Consider the potential for refurbishments Assessments for infrastructure improvements to reduce energy consumption are complex and you may need to ask for help. Consider the following: 1. Heating controls: If you cannot adequately control the pool hall or changing room heating, or if you are missing thermostatic control valves consider investing in improved controls. 2. Hot water time controls: If you do not have the ability to control the times at which hot water is provided for showering you should install time controls. 3. Pool covers: If you do not already have one installed, these can provide significant energy savings. 4. Energy efficient lighting and automatic controls: Lighting upgrades can make significant energy savings, particularly if you have sodium or metal halide lighting that cannot be easily switched off during the day. 5. Boiler efficiency: Investigate whether old conventional boilers can be replaced with high efficiency condensing boilers, or even combined heat and power (CHP) if your pool is used year-round. 6. Insulation improvements: You should aim to insulate all hot pipework and valves to minimise heat losses. Install any missing insulation on pipework and use easily removable valve jackets to cover valves. 7. Improved electricity/gas metering: If you cannot directly separate your pool s electricity/gas consumption from that of the rest of the school, sub-meters can allow you to do this. 8. Showers: install push button controls and aerating shower heads to reduce the amount of hot water used. 9. Heat recovery from backwashing: some pool systems can be suitable for this to be retrofitted if it is not already installed. 10. Ventilation and pumping improvements, consider the following if not already installed: Heat recovery for the ventilation system Humidity controls for ventilation system Variable speed drives for pumps and fans. 11

13 STEP 5: Monitor on-going performance in order to maintain savings Task 1: Record, monitor and refine Moving forward, record your monthly fuel consumption figures and use the information to create a simple bar graph. Whilst the consumption figures for individual months will vary depending on the weather, you will hopefully see a general decrease in consumption as your control adjustments take effect. You should refer to this five step-approach and carry out the tasks at least once a term and keep a record of your findings and any adjustments made so that you can monitor your progress. The appended calculation sheets and walk around checklist provide a template for you to record your findings and calculate a useful estimate of approximate savings that will be achieved. 12

14 Walk around check list for swimming pools: Record your values and circle the appropriate actions to follow up on. 1. What is the pool water temperature?... C Is it appropriate? (See table page 7 for list of temperatures) 2. What is the pool hall air temperature?... C Is it 1 C higher than the pool water temperature? 3. What is the pool hall humidity?...%rh Is it appropriate? (See page 8 for guidance) (Note: excessive humidity can lead to corrosion and structural problems.) Yes No further action required. No see page 7 for guidance on adjusting temperatures. Yes No further action required. No see page 8 for guidance on adjusting temperatures. Yes No further action required. No seek further guidance. 4. Is there a pool cover that is used when the pool is not in use Yes No further action required. No see page 9 for guidance on pool covers. 5. Are heating systems in the changing rooms and other ancillary areas managed correctly? 6. Are lights switched off when areas are not in use or when there is sufficient natural daylight available? 7. Is the amount of hot water heated for the showers an appropriate quantity to meet demand? 8. Are there any potential areas for refurbishment to save energy? If you answered No to any of the previous questions you may need to consider investment to save energy. Potential improvements include: improved controls, pool covers if not in place, improved ventilation, time controls for hot water for showers and improvements to lighting. Yes No further action required. No see page 11 for guidance. Yes No further action required. No see page 12 for guidance on lighting. Yes No further action required. No see page 13 for guidance. Yes seek further guidance. No No further action required. Now complete your savings calculators to see what you can save. 13

15 SAVINGS CALCULATORS You can calculate your approximate savings by following these steps The following calculators will enable you to calculate approximate savings from implementing the measures outlined in this document. These are ball park estimates only and should not be relied on for any investment decisions. Each calculator is colour and symbol coded according to whether it is a basic or more advanced measure as in the main document. The calculator number refers to the Step and Task in the main document (i.e. calculator 2.2 refers to Step 2, Task 2). Note: The calculators are designed to avoid the risk of double counting of savings when more than one savings activity is carried out. Please work through each calculator in turn, putting a zero in the % reduction in heating costs box for any measure that has not been implemented. The financial and carbon savings can be estimated as follows... CALCULATOR 2.2 Annual energy costs INDOOR POOL: If you do not have separate metering for your pool: Record your pool area in m 2 m 2 A Typical annual pool gas or oil cost A x 128 = B Typical annual pool electricity cost A x 66 = C OR INDOOR POOL or OUTDOOR POOL: If have separate metering for your pool: Record your annual pool gas or oil cost B Record your annual pool electricity cost C CALCULATOR 3.1 Adjustments to pool water temperature control How many C have you reduced your pool temperature? C D % reduction in gas or oil cost 5 x D = % E Reduction in annual gas or oil cost E x B/100 = F Remaining annual gas or oil cost B F = B 1 14

16 CALCULATOR 3.2 Adjustments to pool hall air temperature control How many C have you reduced your pool hall air temperature? C G % reduction in gas or oil cost 5 x G = % H Reduction in annual gas or oil cost H x B 1 /100 = I Remaining annual gas or oil cost B 1 I = B 2 CALCULATOR 3.3 Pool hall humidity How many RH % points have you increased your pool hall s humidity by? % Reduction in gas or oil cost 0.75 x J = % K Reduction in annual gas or oil cost K x B 2 /100 = L J Remaining annual gas or oil cost B 2 L = B 3 Reduction in annual electricity cost K x C/100 = M Remaining annual electricity cost C M = C 1 CALCULATOR 3.4 Use of pool cover Reduction in annual gas or oil cost 10 x B 3 /100 = N Remaining annual gas or oil cost B 3 N = B 4 CALCULATOR 4.1 Ancillary area heating controls How many hours per day have you reduced your heating time by P (on average)? % Reduction in gas or oil cost 0.5 x P = Q Reduction in annual gas or oil cost Q x B 4 /100 = R Remaining annual gas or oil cost B 4 R = B 5 How many C have you reduced your room temperatures by S (on average)? % Reduction in gas or oil cost 0.5 x P = T Reduction in annual gas or oil cost T x B 5 /100 = U 15

17 Remaining annual gas or oil cost B 5 U = B 6 CALCULATOR 4.2 Pool lighting improved control Reduction in annual electricity cost 3.0 x C 1 /100 = V Remaining annual electricity cost C 1 V = C 2 TOTALS CALCULATOR Total reduction in annual gas or oil cost from tasks carried out B - B 6 = W Approximate reduction in annual CO 2 emissions from gas or oil W/165 = tco 2 X Total reduction in annual electricity cost from tasks carried out C C 2 = Y Approximate reduction in annual CO 2 emissions from electricity Y/165 = tco 2 Z 16