Types of Commercial Water Heaters: Feel the Heat this Valentine’s Day
When it comes to commercial water heaters, building owners and tenants have several options to choose from, each with its own set of advantages and disadvantages. As plumbing engineers, we know that understanding these options is crucial for recommending the best solutions to our clients. In this blog post, we’ll explore the different types of commercial water heaters, including electric resistance, heat pump, gas-fired, and the differences between tankless and storage tank types. We’ll also touch on the Denver Energy Code changes and restrictions related to service water heating. Our goal is to help everyone “feel the heat” this Valentine’s Day! Tankless vs. Storage Tank Water Heaters Another significant decision to face is choosing between tankless and storage tank water heaters. Each type has its own set of benefits and drawbacks. Denver Energy Code Restrictions The Denver Energy Code has specific restrictions on the types of water heaters that can be installed in new and existing commercial buildings. As of March 1, 2023, the code requires partial electrification for all existing commercial and multifamily buildings when replacing gas-fired space and water heating equipment. This means that gas-fired water heaters are being phased out in favor of more energy-efficient options like electric heat pump water heaters. For commercial buildings, the Denver Energy Code also encourages the use of electric heat pump water heaters and restricts the installation of new gas-fired water heaters. These changes are part of Denver’s broader efforts to reduce carbon emissions and promote sustainable building practices. Valentine’s Day Jokes And because you asked for it, here are some Valentine-themed jokes to help everyone feel the heat (or maybe just make us plumbing engineers chuckle): Conclusion Choosing the right water heater for a commercial building involves considering various factors, including energy efficiency, operating costs, and installation requirements. Electric resistance, heat pump, gas-fired, storage, and tankless water heaters each have their own advantages and disadvantages. Understanding these options and the local energy code restrictions can help businesses make informed decisions. Whether you’re a business owner, plumber, or engineer, understanding the intricacies of water heaters is key to ensuring a comfortable working environment—just like keeping the warmth alive in your Valentine’s heart!
Hot Water Decoded: An Introductory Guide to Water Heaters
As the name suggests, water heaters are equipment that will raise water temperature. Water heaters come in many shapes and sizes but can be characterized by storage and energy sources. Storage methods are tank or tankless; the energy source is electricity or fossil fuels. Tank water heaters, also called “storage” type water heaters, hold a set volume of water that is heated through prolonged contact with the internal heating components. Tankless, or “instant,” water heaters use a much higher energy input to heat the water to the desired temperature as it flows to the fixture. There are two main ways to use electricity to heat water, one being electric resistance and the other by using the electricity to run a heat-pump refrigerant cycle. Electric resistance-style heating elements are simple and have no moving parts, but the energy output is equal to the energy consumed by the coil. Although heat-pump water heaters also use electricity to operate, they “move” heat instead of “creating” it. This process is a more efficient way of heating water, allowing heat pump water heaters to be up to 410% more efficient than an equivalent resistance style. Water heaters that use fossil fuels as the energy source are usually referred to as gas water heaters. The options for source types are most commonly natural gas or propane. Natural gas is the fossil fuel utility most often offered by service providers, while propane is usually shipped and stored in tanks on-site. Although most gas water heaters are similar, the most noticeable difference is between condensing and non-condensing style burners. When gas-fired equipment burns fuel, it doesn’t use 100% of the energy released from combustion, resulting in a mixture of unburnt fuel and water vapor. If cooled enough, the flue gases can condense on the flue vent piping, leading to corrosion. Hence, manufacturers reserve approximately 20% of the energy released to keep the flue gas temperatures high enough to prevent condensation. More modern gas-fired water heaters will utilize the condensation to put more energy into the water instead of keeping the flue vent gases hot, resulting in efficiencies up to 98%. The corrosive condensate produced by this process is handled by using resilient metals for the heat exchanger and acid-neutralization kits to ensure the condensation produced is safe for sanitary lines and treatment plants. Tank-Type Water Heaters Pros Cons Tankless Water Heaters Pros Cons Electric Resistance Water Heaters Pros Cons Heat Pump Water Heaters Pros Cons Gas-Fired Water Heaters Pros Cons
Flowing Forward: Basics in Graywater Recycling and Water Conservation
With climate patterns changing and becoming more unpredictable, water conservation measures are becoming critical to reduce water consumption in our buildings. One way to reduce water consumption and decrease your water utility bill is to utilize a graywater recycling system. Below, we will explore graywater and graywater recycling systems, where they are best to be implemented, and what the requirements are around these systems. What is Graywater? Let’s start with the basics. What is graywater? Graywater is nonpotable wastewater from washing machines, showers, bathtubs, lavatories, and HVAC Condensate. It can be treated and recycled for use in water closets/urinals and irrigation systems to reduce your building’s domestic water consumption and wastewater quantity. Graywater is piped separately from the building’s main wastewater system and is routed from the designated fixtures providing graywater to a graywater treatment (if required) and storage system. The exact components of this system will depend on your manufacturer and authority having jurisdiction (AHJ) but it typically consists of a water treatment system, a storage tank, and a pump. The treated graywater will then be routed to the water closets and irrigation systems designed to be served from the graywater systems. Even though the graywater may go through a treatment system, it is important to note that this water is still not potable. Is a Graywater System Right for Your Building? Now that we know what a graywater system is, when is a graywater system right for your project/building? To utilize a graywater system to the fullest extent, the project should have a steady and consistent usage of the fixtures supplying the graywater system. Buildings with consistent shower and/or laundry usage provide the best supply to a graywater system. This could apply to hotels, multi-family, fitness/recreation centers, police departments, etc. Buildings without shower or laundry usage can still be a good candidate, but the graywater system may not be capable of providing the water for all the water closets or irrigation needs since the waste from lavatories will typically not equate to the water closet and irrigation usage. A review of the feasibility of a graywater system for a building can be done during the pre-design or schematic design phases with the plumbing engineer and a graywater system manufacturer to determine if it’s a good application for the project. Requirements In conjunction with evaluating if a graywater system is suitable for your building based on building type and fixture usage, it will need to be determined that the AHJ allows graywater systems and if they have any special requirements for the system. The City of Denver, for example, allows and encourages graywater systems, but a graywater system installed in the City and County of Denver must meet the requirements of Denver’s Graywater Use Program, which can be found on the city’s website and outlines requirements for graywater systems used for irrigation and toilets/urinals. These requirements include treatment, signage, watercolor, testing, and permitting needs. Implementation We have now determined that a graywater system is a good application for our project, and the AHJ allows graywater systems. That great! So, what is next? During the early design phase, the engineer will need to work with the architect and other consultants to ensure the proper location and space are allocated for the system. The graywater system will preferably be located in a room below the fixtures providing graywater so the waste can gravity drain into the treatment/storage system. Ideally, this would be located in a basement. The engineer will also need to determine the required system components based on the application and AHJ to ensure proper space is allocated for the equipment. The system could include treatment equipment, storage tanks, pumps, backflow preventors, valves, etc., so ensuring space is appropriately allocated for this equipment early is critical. If the proper location and space are allocated for the graywater system early, this should set up the design for the remainder of the project. Overall, a graywater system can be a great way to conserve water usage in your building and decrease water utility costs. Prior to implementing a graywater system in a building’s design, the building’s fixture use should be evaluated for the impact of the graywater system, along with confirming the AHJ requirements for graywater systems to ensure it’s the right approach for the project. Resources:
Elevating Aesthetics While Minimizing Cost Impacts
HVAC and plumbing systems are essential to creating a comfortable and productive environment in our buildings; however, nothing can bring down the look of a well-designed space more than a misplaced diffuser or unexpected thermostat. In most instances, concealing HVAC and plumbing designs into high-finish spaces can come with major cost impacts, but there are simple ways to elevate the integration of these systems into a space without major impacts on the budget. Let’s explore a few! Alignment of Ceiling Devices Aligning diffusers with other ceiling devices is a small task but can have a big impact on the uniformity of the ceiling to provide a clean and organized look. The goal of this approach would be to align diffusers and other ceiling devices to the centerline of the lights, along with creating uniform spacing between the diffuser and other ceiling devices. To ensure the engineer has time to coordinate the final diffuser and device locations, the final locations of lights and other ceiling components should be provided around 75-80% CDs for final alignment. If the aesthetics of a space is a priority, having an RCP coordination meeting between the architect, electrical engineer, and mechanical engineer can be very beneficial to talk through the priority of devices and ensure all parties are fully coordinated. Elevate the Diffuser Specifications Standard cone, louvered, or perforated diffusers can be swapped out to a square plaque diffuser for both the supply and return in the ceiling for a small cost increase ($20-$30/diffuser*). If both the supply and return diffusers are revised to this specification, this can create a clean, uniform look in the ceiling. Square plaque diffusers have a very efficient supply air distribution, providing low-pressure drop and low sound levels with efficient mixing. However, it should be considered when using this specification for return air that this diffuser has less return capacity than other return diffusers with more free area, so additional return grilles may need to be added with this specification. In addition to revising the specifications for square ceiling diffusers, there are many aesthetically pleasing grilles and slots that can be incorporated into the design for supply and return air. The architect should coordinate with the mechanical engineer early in the design process to discuss linear grilles or slot diffuser options to ensure these are properly coordinated into the ceiling and wall details. Although linear grilles and slot diffusers can add significant cost compared to standard louvered grilles or diffusers, applying slots to strategic spaces like lobbies or conference rooms can elevate these common spaces and set the tone for the rest of the building. Coordinating Thermostat Locations and Specifications When placing the thermostats on the plans, the engineer must be strategic with the placement to ensure optimal control of the mechanical system. If this is not properly coordinated during design, this can lead to unexpected locations on the wall come time for the final punch. When we are placing thermostats in the design, we are considering the following: direct sunlight, exterior walls, the path of supply airflow, proximity to major heat-producing equipment, location within the occupied/breathing zone, and many more. In some spaces, these considerations can make thermostat placement challenging. For proper placement coordination, the architect should review the proposed thermostat locations on the drawings once the engineer has laid them out to ensure the locations do not conflict with their design. For more complex spaces, deeper coordination may be required to shift around the thermostats or even shift wall finishes around to accommodate the ideal thermostat location. A coordination meeting between the architect and mechanical engineer may be ideal for these more complex applications. If local control of the temperature setpoint in the space is not required, remote temperature sensors can be considered for minimal added cost. This would locate a thermostat in a concealed or central location for temperature adjustment (If DDC controls are provided, this could be provided via a web-based controller) with a remote temperature sensor placed in the space being measured. There are several types of remote temperature sensors available, including button-style sensors that are about 1” in diameter and can be stainless steel, brass, or paintable and can be easily integrated into the design. Although these recommendations are simple, they can be effective if proactive coordination is achieved. Having upfront discussions on the design intent of the mechanical and plumbing system integration throughout the project will help the engineer provide solutions early to achieve the aesthetic goals of the space. Additionally, if the aesthetics of these systems are a priority in a space, but the budget is tight, these simple solutions and several others can be applied without busting the budget.