Specifications

ManualsBrandsSeresco ManualsDehumidifierNE Series

Seresco Design Checklist

for Traditional* Pools

Having a checklist comes in handy when designing complex jobs. Seresco is pleased to

provide this dehumidification design checklist for your convenience. We also provide our

complete Natatorium Design Guide online, along with extensive specification and design

resources, including load calculation software.

Please visit: www.SerescoDehumidifiers.com/engineers.html

Key Design concerns for traditional* pools:

1. Operating conditions in writing from end user.

(pool water temperature, room air temperature)

2. System supply CFM delivers 4-6 air changes per

hour. The room volume dictates the supply CFM.

Supply air gets to the ‘breathing zone’.

Return duct location compliments supply duct.

No short circuiting.

3. Outdoor air CFM per Standard 62

Baseline: 0.48 CFM/ft² of water and wet deck for

regular pool.

Add 7.5 CFM per spectator (swimmers are not

considered spectators and are covered in the

baseline OA CFM).

4. Exhaust Air

Room is at slight negative pressure (0.05 to

0.15 inches of water column)

110% the outdoor air CFM is generally

recommended

Source capture contaminants – Exhaust air

drawn from the whirlpool or any other warm or

highly active water area.

5. Load Calculation

Latent load (pools, OA and spectators)

Sensible cooling load has been calculated for the

space design temperature.

Heating load has been calculated for the space

design temperature and includes OA.

6. Condensation and Vapor Migration

Vapor barrier on the warm side of the dew point

temperature in all walls, ceiling and floors.

All exterior windows, doors and skylights are fully

blanketed with supply air (3-5 cfm per sq ft).

7. Energy & LEEDs Considerations

Energy Standard 90.1 – pool water

heating option

Heat recovery between the minimum OA and

minimum EA

Condensate reclaim

System refrigerant charge reduction –

Protocol Design

8. Swim Meet Mode

Number of spectators and competitors

expected?

Spectator areas

Airflow to spectator seating areas

Micro climate via separate air handler for larger

spectator areas

9. Service and Maintenance

Internet monitoring

Unit is accessible

Unit has adequate service clearance

* Please contact factory for Waterparks and pools heavy with

water features. Design standards have been established for

‘traditional’ bodies of water and do not adequately address

the special needs of these facilities.

www.SerescoDehumidifiers.com

Seresco USA Tel: 770.457.3392

Seresco Canada Tel: 613.741.3603

Summary of content (37 pages)

PAGE 1
Seresco Design Checklist for Traditional* Pools Having a checklist comes in handy when designing complex jobs. Seresco is pleased to provide this dehumidification design checklist for your convenience. We also provide our complete Natatorium Design Guide online, along with extensive specification and design resources, including load calculation software. Please visit: www.SerescoDehumidifiers.com/engineers.html Key Design concerns for traditional* pools: 1. Operating conditions in writing from end user.
PAGE 3
About the Author – Ralph Kittler, P. Eng. The creation of Seresco’s Natatorium Design Guide has been a collaboration of input from four of Seresco’s senior engineers and founding partners, led by Ralph Kittler. Quite simply, nobody in the industry has better credentials than Ralph to create all of our Natatorium Design related educational materials. In addition to being a founding partner of Seresco Technologies, Ralph is an ASHRAE “Distinguished Lecturer” and ASHRAE Technical Committee 8.
PAGE 4
Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Comfort, Health and Safety . . . . . . . . . . . . . . . . . . 6 Comfort and Health . . . . . . . . . . . . . . . . . . . . . . . 6 Humidity Control Calculations . . . . . . . . . . . . . . . . 7 Load Calculation . . . . . . . . . . . . . . . . . . . . . . . . . 7 Pool Evaporation . . . . . . . . . . . . . . . . . . . . . . . . . 7 Occupant Load . .
PAGE 5
Introduction Natatorium design is a complex business with serious energy, comfort, health, and safety considerations. Heat, humidity and chemicals in pools combine to create harsh environments that are hard on buildings and hard on equipment. Providing a safe, healthy and comfortable pool environment while minimizing operating costs and delivering the best possible air quality is no simple task.
PAGE 6
The Basics The natatorium experience for a patron should be no different than any other room in a building. It should be comfortable, healthy and have good air quality. When designing a natatorium the first recommended step for the designers is to meet with the facility owners to discuss the desired operation and expectations for their natatorium. Only once the operating conditions and expectations are defined, can the designer effectively calculate loads and address all the key design aspects.
PAGE 7
Comfort, Health and Safety A natatorium is one of the most notoriously difficult codes require. More is not better in this case as it facilities to design because there are so many critical causes the RH levels can plummet to as low as 20%, considerations that, if overlooked, can develop into costing the operator in dearly increased air and pool water heating costs.
PAGE 8
General Notes: • Discuss the planned operation of the facility with the operator to establish operating temperatures. • Facilities with warmer water temperatures tend to have warmer space temperatures. • Physical therapy facilities will often cater to therapist comfort rather than the patient. The patient is generally not in the space for more than an hour, whereas the therapist is there all day. The designer should consult local codes.
PAGE 9
water @ 10-30 fpm. The Vapor Pressure values can be found in steam tables. ER ER A AF Pw = 0.1 x A x AF (Pw – Pdp) = evaporation Rate of water, lb/h = area of pool water surface, ft2 = Activity Factor (see Table 2) = saturation vapor pressure at water surface, in. Hg Pdp = partial vapor pressure at room dew point, in.
PAGE 10
The purpose of this outdoor air is to help dilute chemicals off-gassed from water. A predictably dry portion of the deck will not factor into the IAQ issues. Additionally, outdoor air requires considerable heating in the winter. Load Estimation Software Seresco has developed software that calculates all moisture loads in a matter of minutes. On the previous page, Figure 2 gives a snapshot of the basic data that would generally need to be entered to calculate a load. More is not better.
PAGE 11
Refrigerant Reduction: Seresco’s NP Protocol Series dehumidified and reheated air to the space, and warm water to the pool. Not a single BTU on either side of the refrigeration cycle is wasted. COPs are close to 8 and EERs greater than 25! The “Protocol” NP Series is fast becoming the HVAC industry’s new benchmark for indoor swimming pool dehumidifier technology.
PAGE 12
glycol which is 95-percent less expensive and an environmentally-preferred heat transfer fluid for LEED® and other sustainable building projects. All DX systems have outdoor condensers and hot gas reheat coils that flood with liquid refrigerant for extended periods. The result is a large system charge, which aside from being expensive, creates the tendancy for oil migration and premature compressor failure.
PAGE 13
At the moment NP series units are offered starting at 18 HP but all Seresco units can be provided with the dry cooler heat rejection option. Seresco’s innovative heat rejection design makes the Protocol Series equally efficient as DX systems on summer design days and five to seven-percent more efficient throughout the rest of the year. The innovative design uses an active refrigeration head pressure monitor/control that ensures the lowest possible condensing pressures to boost system performance.
PAGE 14
minimum exhaust air CFM requirements are identical for all systems. Table 4 – System Comparison Some promote more outdoor air than codes require in order to ensure good IAQ. This approach does not actually guarantee better air quality but it certainly increases building operating costs. If the air distribution is not done correctly and the conditioned air does not get to the breathing zone, no amount of outside is going to help.
PAGE 15
Chlorine Smell When you walk into an indoor pool and smell a strong chlorine odor, you naturally think it’s caused by too much chlorine in the water. The odor is actually caused by chloramines (combined chlorines) off gassing from the pool water surface. Chloramines are formed in the pool water when there is insufficient free chlorine in the pool to address the nitrogen-containing compounds brought into the pool water by the swimmers.
PAGE 16
• The outdoor air must be preheated to 65°F – If more than 20% of the total airflow is outdoor air or if the winter design temperature is below 10°F • A certified air-balancing contractor must balance the system airflow. Figure 5 – Exhaust Air All Seresco units are equipped with an outdoor air connection, filter and balancing damper. Motorized dampers and time clocks are also available. Exhaust Air ASHRAE recommends the room be maintained at 0.05-0.
PAGE 17
Condensation Control You only have to enjoy a cold drink on a summer day to experience dew point and condensation firsthand. Condensation occurs because the surface temperature on your glass is below the ambient dew point temperature. While 50-60% relative humidity levels are ideal for bather comfort and health they much higher than people than what people are used to seeing in traditional spaces in winter. In northern climates it is very common to humidify in order to get the humidity levels up to 30-40%.
PAGE 18
Therefore, any surface with a temperature below 62°F will condense moisture. Vapor Retarder A vapor retarder is a material that restricts the rate of water vapor diffusion through the ceilings and walls of a building when below dew point temperature occurs. Figure 7 illustrates how failure to install the vapor retarder in the proper location will result in condensation within the structure. Condensation in your walls or roof can lead to structural failure. A vapor retarder should be sealed at all seams.
PAGE 19
Figure 9 – Window Design • • • • air to leak. The location of supply grilles and overall duct layout should be exactly as you would with metal duct. Ductwork that passes through an unconditioned area should be insulated on the exterior. When applicable, locate exhaust fan air intakes as close to the whirlpool as possible. To prevent excessive vibration noise, install neoprene flex connectors when attaching ductwork to the dehumidifier.
PAGE 20
Energy Consumption Considerations Energy consumption and performance implications based on the owner’s choice of operating conditions and building envelope should be discussed in order to ensure there are no surprises. An all glass structure, for example, is going to be expensive to heat and difficult to keep condensation free in a northern climate.
PAGE 21
The mechanical refrigeration system approach to controlling the environment in a pool is a unique use of the refrigeration system. The evaporator controls the humidity while simultaneously the compressor hot gas can be used to heat the pool water and/or room air. Traditional air conditioning systems merely send the compressor hot gas outdoors to a condenser or cooling tower and do not tap into this heat source.
PAGE 22
Figure 12 – Heat Exchanger introduces a lot of moisture and increases the dehumidification load. In northern regions outdoor air in winter may need to be heated 100°F just to get neutral to the space temperature in the pool! The designer has several energy issues to consider: • Introducing more outdoor air than codes is not recommended: -- In winter it will increase space heating and pool water heating costs significantly.
PAGE 23
recovery option that outperforms other technologies and actually fits into a mechanical room. The compact nature if this design results in lighter weight cabinets compared to units integrating plate heat recovery technology. This is an important consideration on applications where roof loads are a concern. The glycol run around loop performance is engineered for a pool application. The coils are fully dipped for corrosion protection and there is no defrost or bypass mode on the coldest winter days.
PAGE 24
Finalizing System Design At the core of every successful natatorium design is a system that provides the operator the year round conditions they expected while meeting ASHRAE design standards, satisfying local codes and being as energy efficient as possible. This design guide has covered many important aspects to consider and putting it all together properly can become a daunting task.
PAGE 25
• Preheat the outdoor air to 65°F to avoid condensation problems. Seresco’s glycol heat recovery loop is a good means to accomplish this while also saving the operator in heating costs. • Thermally insulate the exterior of the outside air duct. Step 4: Exhaust Air The room should have a slight negative pressure. ASHRAE recommends 0.05 to 0.15 inches of water column. A good rule of thumb is to exhaust 110% of the outdoor air CFM.
PAGE 26
Heat Recovery on minimum outdoor air and exhaust air Condensate Reclaim Outdoor ventilation air is essential for maintaining good IAQ in the pool and is a code requirement. The natatorium also needs to be maintained at a slight negative air pressure, so warm energy rich air needs to be exhausted. These two airstreams at vastly different conditions present a perfect opportunity for heat recovery. Seresco provides unit mounted heat recovery between these two air streams using a glycol run-around loop.
PAGE 27
The vertical configuration in Figure 14 is very popular in hotel and residential applications because of their compact footprint and 2-side service access. These PV and NV models are available with or without pool water heating. The maximum size is limited to 100 lb/h capacity. Figure 15 – Typical Hotel and Therapy Pool Layout There are a multitude of other configurations available should a horizontal unit or outdoor packaged system suit the project better.
PAGE 28
Figure 16 – Normal Mode Figure 18 – Purge or Economizer Mode Figure 17 – Normal Mode with Glycol Heat recovery the space with 100% outdoor air to quickly clear out any airborne chemicals. 2. It also allows for a means to deliver a complete air change of the space should it require a quick purge. 3. Built-in economizer operation. All controls and mechanical equipment are already in place to operate in economizer cooling and dehumidification modes whenever the outdoor air conditions are suitable.
PAGE 29
Dehumidifier Specifications In order to ensure the system performs reliably and that the equipment is suitable for an indoor pool environment, there are several items to look for in a quality product. The materials and components used must have adequate corrosion protection. Seresco uses only the best available materials, coatings and paints to ensure the longest possible unit lifespan. For example, the sheet metal used has an automotive grade galvanizing that is intended to withstand road salt.
PAGE 30
Factory certified service companies can now offer pool operators 24-hour monitoring. This is the new standard in customer satisfaction and unit reliability. Refrigerant Pressure Transducers Unit mounted pressure transducers allow the operator or serviceman to access the vital refrigerant pressures through the operator panel of the microprocessor (or remotely via the internet) rather than having to connect a set of refrigerant manifold gauges.
PAGE 31
Design and Installation Details The designer should address the following issues to ensure the unit is properly installed and can be serviced and maintained. Access Space No Access = No Service or Maintenance. All Seresco dehumidifiers have been designed to require access on only two sides. Allow a minimum of 36 inches of clearance on the sides indicated for piping and service access. Mirror access units are also available.
PAGE 32
Figure 20 – Proper Pool Water Heater Piping Installation Design and Installation Details 31
PAGE 33
• Ensure an appropriate maximum ambient air temperature has been specified. • Ensure the unit has proper airflow. A perimeter of free area equal to its width must be provided. • Use line sizes as specified by Seresco. • To avoid potential seasonal system charge problems with outdoor condensers, ensure the installed line lengths are never longer than indicated on the plans and specifications. • If the condenser is installed above the dehumidifier, ensure the hot gas line has proper oil traps.
PAGE 34
• Specify the lines be nitrogen purged while being brazed to help avoid scaling inside the pipe • All the refrigeration requirement disappear with a Protocol or dry cooler system! Control Wiring The NE Series dehumidifiers have all necessary sensors unit mounted and set points pre-programmed at the factory. Remote duct heaters, outdoor air-cooled condensers, auxiliary pool water heaters and remote exhaust fans all require interfacing with the dehumidifier.
PAGE 35
Frequently Asked Questions The Key What is the most important HVAC design aspect in a Natatorium? Get the air distribution right. Get air to the breathing zone. Get your condensation concerns covered. You can do a perfect job everywhere else, but if you don’t get air down to where the occupants are you will have a problem job. If the windows are sweating, you will have a problem. Duct Material What duct material is recommended? Galvanized sheet metal or Fabric Duct are recommended.
PAGE 36
additional outdoor ventilation air requirement for the spectators. The extra outdoor air gets added to the baseline requirement. Condensate Can I return condensate from the Seresco dehumidifier back to my pool? It is recommended that the condensate from the dehumidifier be returned to the pool when local codes permit. This is worth LEED points. The amount of condensation recovered in one year is equivalent to one complete pool fill.
PAGE 37
Seresco Design Checklist for Traditional* Pools Having a checklist comes in handy when designing complex jobs. Seresco is pleased to provide this natatorium design checklist for your convenience. We also provide our complete Natatorium Design Guide online, along with extensive specification and design resources, including load calculation software. Please visit: www.SerescoDehumidifiers.com 1. Operating conditions in writing from end user (pool water temperature, room air temperature) 2.