Hot Water System Considerations for Multi-Storey Buildings

Introduction to Hot Water Systems for Multi-Story Buildings

Selecting a suitable hot water system is crucial for multi-story buildings to ensure consistent and reliable service. With many floors and units to service, these buildings have unique requirements for hot water flow, pressure, efficiency, and reliability. Inappropriate systems can lead to insufficient hot water supply, increased running costs, and tenant frustration.

The main types of hot water systems used in multi-story buildings are central gas systems, pump hot water systems, solar hot water systems, and central electric storage tanks.

Heat pumps and solar hot water systems, harnessing renewable energy, are typically efficient and cost-effective. Electric and gas central systems feature large storage tanks, guaranteeing sufficient hot water during peak demand times.

Building managers must evaluate factors including initial investment, energy efficiency, pressure and flow rates for all floors, maintenance ease, and space for equipment.

Accurate sizing, informed by water meter readings, is critical to avoid shortages, especially in high-usage areas such as kitchens. Consulting with a commercial plumbing specialist is recommended to determine the best service for your multi-story property.

Comparing Hot Water System Types

Introducing the Main Hot Water System Options

For a multi-story building, the primary hot water system options include:

• Gas central heating systems, with a central boiler and storage tank, can provide ample hot water despite incurring higher operational costs.
• Tank continuous systems - These systems also use electric elements to heat water stored in an insulated central tank. Like gas systems, the hot water is then circulated to apartments. Operating costs are influenced by electricity prices.
• Solar water systems utilise solar collectors on the roof that absorb heat from sunlight to warm water being used in the building. This pre-heated water flows into a gas or electric booster system for final heating. Solar systems have lower running costs but are more expensive to install initially.
• Heat pump systems - Extracting ambient heat from the air, pump water heaters use a compressor and refrigerant gas to heat the water. They are energy efficient, which can be more suited to smaller buildings.

Key Factors to Compare the Systems

When deciding on a system for a multi-story building, key factors to weigh up include:

• Upfront system cost and installation - Solar hot water and heat pumps have a higher initial cost. Gas central heating is moderately priced to install.
• Operational costs - Solar and heat pumps have lower running costs due to their renewable energy sources, unlike gas and electric storage tanks which may increase energy expenses.
• Space requirements - Central gas and electric tank systems demand dedicated plant room onsite due to their complexity. Heat pump water systems only need an external compressor unit.
• Efficiency - Properly sized split systems are very energy-efficient, whereas gas and electric tanks incur heat losses.
• Complexity - Centralised systems require extensive installation and maintenance, in contrast to the simpler service needs of heat pumps.

By weighing up these factors against the needs of the multi-story building, plumbing contractors can recommend the most suitable and reliable system.

Gas Systems

Gas central heating systems, which service each apartment, including continuous flow hot options, are a common choice for multi-story buildings due to their ability to deliver adequate hot water pressure and flow rates. A central gas boiler or continuous flow hot water heater generates hot water, determining how much is distributed via pipes to all apartments and common areas.

Gas systems offer an energy-efficient and cost-friendly hot water solution for sizeable buildings. As natural gas prices are lower than electricity, gas systems have lower running costs than electric storage tanks, making building new house with such a system potentially more cost-effective. They also recover faster than electric systems when there is high simultaneous demand across the building.

There are regulations regarding the proximity of gas cylinders and flues to site boundaries and openings. Our team of plumbers can advise you more about the safest locations to situate gas hot water system components, with the right pump water configuration, both internally and externally on the roof. An expert is also needed to ensure correct system sizing to meet the building’s expected peak hot water requirements.

Electric Systems

Electric hot water systems are another common choice for multi-story buildings due to their perceived simplicity. However, their higher operational costs can affect energy bills, notably in new buildings or developments. Electric heating elements are used in storage tanks or continuous flow units to heat water.

For electric systems, selecting a tank with sufficient capacity and heating elements to meet demand is crucial. As electricity is more expensive than gas, it’s important to consider, electric systems, lacking the efficiency of a flow hot water system, have higher energy bills. However, they avoid the need for roof-mounted gas equipment or proximity concerns.

Insufficient capacity results in supply shortfalls, not meeting the building’s hot water needs.

Our electricians can determine how your building’s daily hot water usage informs the proper sizing of electric systems. They can recommend energy-saving tips like tank insulation and timers to improve efficiency. We also stay up to date on regulations for electrical works to ensure compliance.

Solar Systems

Solar hot water systems are an environmentally-friendly option that utilises renewable energy from the sun. Water heaters, including solar collectors mounted on the roof, absorb heat from sunlight, which is transferred to water circulating through the collectors.

This pre-heated water is then directed through a heat exchanger to a booster system, either gas or electric, for final heating before distribution. As solar systems reduce reliance on gas or electricity for water heating, they lower a building’s environmental impact and ongoing energy bills.

In urban areas, securing sufficient unshaded north-facing roof space for extensive solar collectors presents a challenge for multi-story buildings. However, the long-term savings often make these systems a viable investment.

Contemporary solar collectors efficiently heat water to between 30 and 40°C, even under cloudy skies or in winter. Our experienced solar installers assist with factors like system sizing and positioning to maximise efficiency over the year while meeting the full hot water demands.

Heat Pump Systems

Heat pump hot water systems offer energy efficiency suited to the needs of multi-story buildings. They work by extracting heat air from the ambient through an external fan compressor. This heat is absorbed by the unit inside which use heat to warm water held in a storage tank, which is then pumped to apartments as required.

Compared to gas or electric systems, Heat pumps can operate more efficiently by leveraging heat energy that already exists in the ambient air. Avoiding direct gas combustion or electric heating, heat pumps are more efficient with reduced operational costs.

However, the suitability of heat pumps for high-rise buildings may be limited regarding water delivery to upper floors. If mains pressure water delivery is insufficient, booster pumps may be required to push water to upper levels. Check with a plumber whether a heat pump system could fully service your building.

Also consider noise impacts.

The continuous operation of external evaporator fan units produces noticeable noise. Units shouldn’t be installed near open windows where noise might disturb residents. Our team advises on the optimal location to make sure to avoid noise issues as the unit reaches end its operational life.

Placement and Installation Considerations

The placement of hot water systems in an apartment building is critical for ensuring adequate water pressure and minimal heat loss across all floors. As a general rule, systems should be located as close as possible to the most frequently used hot water outlets to reduce piping runs.

In buildings over 3 stories tall, where many people reside, the distance water must travel can make it difficult to maintain pressure. Hydro-pneumatic tanks used with central systems ensure pressurised water delivery across all apartment levels. These tanks maintain water pressure by compressing air on the sealed water side.

To Ensure the system your building utilises is optimally placed, gas and electric central heating systems, providing hot water same as rooftop units, are often situated in basement plant rooms to allow vertical pipes to riser shafts on each level. However, if no suitable plant room exists, a roof-mounted setup may be required. Heat pumps and solar collectors need to be fixed securely to roof structures also.

Our commercial plumbers provide expert guidance to ensure your hot water system is strategically placed for optimal use. The objective is to ensure convenient access, optimal performance, and reliable hot water supply to all levels in compliance with safety standards.

Regulations and Code Compliance

There are important Australian standards and regulations that hot water systems in multi-story buildings need to comply with during installation for safety reasons.

A critical aspect for plumbing systems is the installation of sufficient backflow prevention to protect the drinking supply from contamination. Certified backflow prevention devices must be fitted by law.

Proper fluing and ventilation of gas systems is also critical to safely remove products of combustion, ensuring the quality of water same as the safety standards. Ventilation rules cover aspects like minimum flue heights and proximity to openings and boundaries.

Collaborating with our qualified professionals at Carlingford Plumbing eases the compliance process with complex water system regulations. Our fully licenced and insured plumbers and gas fitters ensure your new or replacement system is fully compliant.

Performance Factors for Multi-Story Buildings

When selecting a hot water system for a multi-story building, it’s vital the system is adequately sized to meet peak demand across all apartments simultaneously. Key calculations involve:

• Amount of hot water usage expected per apartment per day
• Total number of apartments/units
• Allowance for communal facility usage like gyms or pools
• Simultaneous usage factor - the percentage of apartments likely to be using hot water at the same time

For centralised electric and gas systems, the storage cylinder capacity and heating element size/burner output must align to the total anticipated peak demand. Otherwise, your water rates deplete stored hot water faster than the system can reheat it.

We calculate the ideal system size and heating capacity for your building using proven formulas and hot water meter data. Solar collectors and heat pump fan coil units also need proper sizing to handle usage volumes. Although oversizing increases costs, undersized systems lead to ongoing hot water shortages.

Contact our commercial plumbing team to ensure your hot water system in your multi-story building keeps flowing with the right set up for your needs.

Operating Hot Water Efficiently

There are several strategies apartment buildings can use to maximise the efficiency of hot water systems and reduce costs. This is important as multi-story buildings have higher hot water demands across many units.

Regular preventative maintenance is essential to preserve hot water system efficiency. Annual servicing checks and cleans systems, ensuring optimal performance. We also advise on integrating with your existing infrastructure to upgrade to new hot water units with higher efficiency models where viable.

Smart control systems help align hot water usage with solar generation to minimise use of gas or electric boosters. Low-flow taps and showerheads also reduce hot water volumes needed.

Hotel rooms require more compact systems that can recover quickly to accommodate a high guest turnover. Rental units have lower usage than owner-occupier apartments. Analysing the building’s specific requirements leads to efficiency savings by ensuring systems are the correct size.

Noise and Safety Best Practices

With heat pump hot water systems containing external fan coil units, there are some best practises regarding noise and safety in multi-story buildings.

As heat pumps run continuously, moderate operating noise is generated. Units should be professionally installed away from open windows or balconies where noise might disturb residents.

Adhering to council noise regulations is also important. Acoustic enclosures or noise barriers can muffle sound. Anti-vibration mounts under units also reduce vibration transfer through walls and floors for apartments below.

For electrical safety, heat pumps should have an isolating switch installed to safely cut power if maintenance is required. And backup electrical protections systems installed prevent voltage surges damaging the heat pump during blackouts.

Following installer guidelines on the safe height, mounting and clearance space around external heat pump units is critical. This ensures hot exhaust air discharges safely away from public areas on balconies or rooftops in multi-story buildings.