AA GGuuiiddee ttoo aann IInntteeggrraatteedd HHVVAACC SSyysstteemm DDeessiiggnn ffoorr tthhee 2211sstt CCeennttuurryy NNaattaattoorriiuumm Foreword Contents Desert Aire has written this document to provide owners, Overview ..................................................................... 3 mechanical contractors and engineers with a helpful guide • e Purpose of the Natatorium to designing or retrofitting an indoor pool facility. • e Goals of HVAC Design Heating, Cooling and Moisture Load Just in the past few years there has been a major break - Determination ............................................................ 4 through in understanding the complexity of maintaining • Air and water temperatures the indoor air quality of a pool facility. is guide tries to • Relative humidity tie together the many independent elements of a very complex • Airflow across water HVAC system, building structure, water loop, facility • Activity factor programming and energy consumption. For too long these • Spectator load elements were designed independently and rarely was an • Ventilation load effort made to integrate them to create the best indoor pool for all stakeholders. Condensation and Building Integrity .................... 7 • Dew point control It is our expectation that this guide will assist in developing • Vapor barrier the dialog to solve problems in existing designs as well as • Negative pressure serve as the benchmark for new construction. e guide • Spectator areas will also refer to other documents or industry knowledge Swimmer Health Concerns ....................................... 11 to support creation of final design specifications and the • Toxic air construction document. • Most common airborne contaminants • Source capture solution This guide will be a living document so we welcome the • Pool chemical usage opportunity to receive your feedback on innovations and • Chlorine innovative thinking that can help produce the highest • Chlorine alternatives quality indoor pool facility. Feel free to reach out to any • Salt water pools Desert Aire sales representative or staff member with your Proper Airflow Design .............................................. 13 feedback. • Duct design • Supply air rate Dehumidification Equipment Design Consideration s ............................................................ 15 • Dehumidifier system components • Dehumidifier design options Keith Coursin • Economizers President • Purge mode Desert Aire Corp. • Maximizing energy recovery [email protected] • Integrated with source capture • Low exhaust energy recovery • Installation considerations Commissioning ........................................................... 22 • Factory certified start-up • Facility staff training Conclusions .................................................................. 22 3 AA GGuuiiddee ttoo aann IInntteeggrraatteedd HHVVAACC SSyysstteemm DDeessiiggnn ffoorr tthhee 2211sstt CCeennttuurryy NNaattaattoorriiuumm Overview Objectives now include protecting the health of swimmers, divers, coaches and spectators; promoting the long-term The Purpose of the Natatorium structural integrity of the building and supporting systems; and conserving energy, water and water treatment resources. e natatorium is a building that contains one or more aquatic venues and structures where the general public is But there is a guiding principle that applies to HVAC system exposed to water intended for recreational or therapeutic use. design no matter the purpose, size and location of the natatorium: the HVAC system must work in harmony with Although we most oen think of aquatic venues as indoor systems that control water temperature and water quality. pool facilities for swimming and diving, they may not only contain standing water. The term can be used to describe For engineers who must translate these objectives into indoor water parks where the public is exposed to water by design goals an integrated, sustainable approach is required. contact or spraying, such as with waterslide landing pools These design goals must reconcile the intensive tasks of and spray pads. dehumidifying the space, heating and cooling the interior, heating pool water, and meeting outdoor air requirements. A natatorium can be housed in a dedicated building or non- dedicated building such as a school building or fitness club. Fortunately, today’s design engineers have access to a range e natatorium may also house locker rooms, lavatories and of problem-solving equipment technologies and strategies. offices. Locker rooms, staff offices and storage rooms should ese technologies and strategies complement resources not be part of the pool room mechanical HVAC system. made available by professional associations and engineering societies; and the goals manifest in building codes and is design guide focuses on larger natatoriums and aquatic standards. For example, the American Society of Heating, centers but many of the concepts would apply to smaller Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE) commercial and residential indoor pool facilities. provides guidance and resources for pool room design. The Goals of HVAC Design e Model Aquatic Health Code (MAHC), published by the e many ways people use buildings with enclosed pools for Centers for Disease Control and Prevention (CDC), is a recreational, competitive and health purposes continue to more recent addition to the resources available to mechanical evolve. ese uses place demands on HVAC systems and on the engineers. buildings themselves that weren’t present even a generation ago. Fortunately, there are advances in knowledge, under - First published in late 2014, the MAHC is a set of guidelines standing, strategies and technology that meet the challenges for public aquatic facilities. According to the CDC, the of today’s natatorium. MAHC “brings together the latest knowledge based on science and best practices to help state and local government Reflecting the depth and breadth of demands, the scope of officials develop pool codes. Pool codes are specific rules that HVAC design considerations for large natatoriums and designers, builders, and managers of spas, pools, waterparks, aquatic centers has expanded in the 21st Century. and interactive fountains must follow to keep the fun going and reduce injuries and illnesses.” 4 e MAHC encompasses traditional aquatic venues such as To calculate heating, cooling and moisture loads to specify and those enclosing swimming pools and spas. e MAHC also size HVAC equipment, these loads are expressed as sensible covers contemporary water-containing structures including and latent. Sensible heat and loads are the heat swimmers wave pools, surf pools, therapy pools and spray pads. and building users feel on their bodies and are temperatures that can be measured by a thermometer. Latent heat and As part of bringing together the best knowledge and practices, loads are the energy and heat stored in humidity, a product the MAHC states the design, construction and installation of its change in state from liquid to gaseous. These two of indoor aquatic facility air handling systems shall comply components when combined provide the total system rating with local codes as well as the proven ASHRAE standard that the HVAC equipment must be designed to remove. 62.1 2013, Ventilation for Acceptable Indoor Air Quality. e overarching goal in managing heating, cooling and Together, this matrix of technologies and strategies provides moisture loads is sustainability: ensuring the natatorium can mechanical engineers with essential tools for balancing continue to fulfill the purposes for which it was built in diverse operating conditions, seasonal variations and special a safe and cost-effective manner. Related HVAC design event needs with building codes and standards for the considerations, as stated earlier, are protecting the health of ongoing, critical concerns of indoor air quality and relative swimmers, divers, coaches and spectators; promoting the humidity. long-term structural integrity of the building and supporting systems; and conserving energy, water and water treatment Heating, Cooling and Moisture resources. Load Determination e ASHRAE Applications Handbook provides formulas for calculating the natatorium moisture load. e factors that e heating, cooling and moisture loads of a natatorium are are used in those formulas include the air and water temper - a product of seasonal variations in outdoor air temperature atures, relative humidity, airflow rate across the water, activity and humidity, solar gains and losses as well as the presence factor, spectator load, and the ventilation load. Each of those of spectators and bleacher areas. will be discussed below. • The heating load is the amount of heat energy that must be added to the natatorium to achieve or maintain a target temperature level. This is often considered the heat loss calculation and is a dominant factor due to the high internal design temperature of an indoor pool area. • The cooling load is the amount of heat energy that needs to be removed to attain the target temperature. is is the heat gain calculation with solar gain and lighting heat being the most significant portions of this load. Figure 1. A pool room with an overwhelmed HVAC system . • e moisture load is the amount of moisture that needs to be removed to attain a target relative humidity level. A pool room that does not maintain the proper temperature The moisture load has three components: evaporation of its air and pool water along with