hot water system presentation slide

The Installation of Hot Water Supply

for Hotel / Corporate Building

Types of Hot Water Systems

Localised Systems Centralised Systems

Instantaneous Storage Tanks Vented Unvented

Direct Indirect

Electric Immersion Gas Boiler Solar Powered

Localised Hot Water Systems

A system in which water is heated

locally to its needs.

Instantaneous water heaters

• heats flowing water

• water flows through a heating

element

• controlled by a flow switch

• 0.05 litres output flow

Storage tank water heaters

• stores heated water in a tank

• water flows through electric

immersion heater

• controlled by thermostat

• temperature and pressure relief

valves

• 7-130 litres output flow

Centralised Hot Water Systems

A system in which water is heated

and stored centrally within the

building, supplying water through

a system of pipework.

Centralised systems consists of:

- Water heaters

- Hot water storage cylinders

- Cold water storage

cistern/Expansion vessel

Water heating system + Pipework

system

Centralised systems can be

separated into:

Vented systems

Unvented systems

Centralised Hot Water Systems

As water expands when heated, some sort of device must incorporated to

accommodate expansion of the hot water storage cylinder. Expansion vessels are

installed to provide an outlet to allow air to escape.

Vented

• cold water supplied from storage tank

• lower water pressures

Unvented

• cold water supplied directly from

mains

• higher water pressures

Vented Hot Water Heating Systems (Centralised)

Vented hot water cylinder has a cold water is supplied from a storage tank.

• to enable trapped air to escape

• to act as expansion tank - accommodate expansion of hot water

Directly

• uses the principle of convection

• heated directly in the storage vessel

Indirectly

• uses an expansion and feed cistern

• water flowed into boiler through primary flow

and return pipes

• heat energy is transferred indirectly

Types of Hot Water Heaters

Gas Fired

• used in both instantaneous

and storage water heaters

• continuous pilot flame ignites

gas flowing through burner

• heat from flame transferred to

water

Electric Immersion

• most common type of water

heater in Malaysia

• used in both instantaneous

and storage water heaters

• immersion heater placed in

water (transfers heat)

• all electricity converted to heat

Solar

• includes storage tanks and

solar collectors

• solar energy used to heat up

water

• solar energy converted to heat

Advantages and disadvantages of different

types of hot water supply system

Tank and Tankless

Comparison Storage Tank Tankless

CONVENIENCE Pre-heat limited water,

refills

and reheat

Provide hot water

sufficiently

EFFICIENCY Operates

continuously, wasted

energy

Heat water on

demand, save energy

COST Less up front but

higher cost to run and

wear out

Slightly more up front

but reduce energy

cost by 60% or more

INSTALALTION &

MAINTENANCE

Most tanks last only

10-12 years. Minerals

build up inside tank

Last up to 20 years

with very little

maintenance

Centralised system and localised systemCentralised system Localised system

require large storage space saves in boiler house space

and fuel store

long length of secondary

pipework will cause large

heat losses

if the unit fails, can carry the

load

one central plant implies

simpler and less maintenance

the number of heater is

added, more gas or electrical

connection

better control in energy

consumption

the risk of fire will increase

reduction in flue construction structural or architectural

aspects may restrict the use

of cheaper fuel

Installation of Hot Water Systems in Hotels

Installation of Hot Water Supply Systems

The main considerations that need to be

taken in to design a hot water supply

system includes:

1. Type of hot water supply system

• Localised or Centralised?

• Direct or Indirect?

2. Supply pipes and water circulation

design

• Location of water heaters

• Piping configurations

• Circulation design

• Zoning

3. Hot Water Heaters

• Electric or Gas?

• Instantaneous or Storage?

Centralised system

Localised system

Zoning

Recirculating

system

Installation of Hot Water Supply Systems

Additional considerations that need to be taken in

to design a hot water supply system includes:

1. Cost and efficiency of the system

• Standby loss

• Tank insulation

• Heat traps

2. Installation and maintenance cost

• Management

• Central hot water generator

3. Storage and distribution temperature

• Stored at approx. 55˚C

• Micro-bacteria (Legionella)

4. Hot water demand requirements

• Water temperature requirements

• Peak periods (Mornings & Evenings)

Insulation

Thermostatic Mixing Valve

Heat traps

Types of piping used

for hot water supply system

TYPE OF PIPE

COPPER PIPE

TYPE OF PIPE

CROSS-LINK POLYETHYLENE (PEX)

TYPE OF PIPE

POLYVINYL CHLORIDE (PVC)

TYPE OF PIPEIt’s a galvanized pipe

steel or iron pipe that

has been galvanized

with zinc coating

GALVANIZED PIPE

CASE STUDY

U-Residence( local)

Best Western Plus New Englander

Hotel( oversea )

Case Study 1 ( Local)

U-Residence @ Syopz Mall, Taylor’s University Lakeside Campus

• Localized hot water system

• The builiding consists of 128 apartments

• Each apartment consist 6 rooms and 1 shared bathroom

• Each bathroom has 2 water closet and 2 shower room

• Each bathroom is fixed with 2 electrical water heater

• Total has 256 hot water heater

• Capacity of water heater is 135 liter

• Heating element voltage is 9kW

• Temperature of hot water stored is 35 degree celcius

HOW IT WORKS ???

1. Cold water is supplied through the blue piping to water heater storage

2. The water heated in a very short time

3. The hot water is then flows out through copper piping to shower head

Case Study 2 ( Overseas )Best Western Plus New Englander Hotel @ Woburn , Massachusetts, USA

Consists of 99

rooms, which

include 2

commercial

washing machines

in it

OLD HOT WATER SUPPLY SYSTEM

Old gas-fired boiler

Storage tank can store up to 1800 liters of hot water

Leakage of water in tank happens

NEW HOT WATER SUPPLY SYSTEM

• Unvented centralized hot water system

• Gas-fired condensing tankless water heaters

• Installed 10 gas-fired condensing water heaters

• The system able to deliver up to 405 liters of hot water per minute

• Temperature of hot water supplied is around 60 degree Celcius

OPERATING SYSTEM

This can

save the

fuel and

electricity

bill

The operating

system of this hot

water supply

system is using

intelligent

cascading

This hotel

has 1

primary

appliance

and 9

secondary

appliances

A signal is sent

to one or more

secondary to

ignite

When the

demand of hot

water is higher

than what primary

appliance can

serve

One of the

appliance serves

as primary

appliance and

attempts to meet

the hot water

demand

Maintenance to maintain the

efficiency of the hot water system

A poorly maintained water heater

system will increase the running

cost and thus, to maintain the

efficiency of the system in long term,

periodic maintenance is necessary. it

will neither consume much time nor

costly unless the system deteriorated

to a point of needing major work or

replacement.

“ Prevention is better than cure “

MaintenanceRegular Inspection

MaintenanceT&P Relief Valve

• checks for cracks, wearing and leaking in piping and ducting

• for solar heating system, check dampers, supporting structures and

flashing and sealant around roof penetrations

• for gas water heater, check if there’s gas leakage

• an equipment that ensures the stability of temperature and pressure of the tank

• a faulty T&P relief valve with high water pressure as a result of runaway overheating will cause explosive steam

Maintenance Water Softener

MaintenanceChlorine

water softener or mild acidic solution can be added every 3-5 years to :

• prevent scaling

• decrease the risk of microbial settlement

• reduce the possibility of water getting infected by microorganism

• to avoid bacterial contamination particularly Legionella

• chlorine inspection should be done anually

• suitable range (0.5mg – 1.0mg)

[ excess may cause chest pain and eye irritation ]

Maintenance Drain

MaintenanceAnti-Freeze

flushing out minerals and other debris that may cause it to malfunction

• prevent scaling

• extend the heater life span

• only occurs during cold climate that falls below 6 degree Celcius

• should be changed every 3-5 years

Problems that might occur in hot water supply system

Problems

Future

Recommendatio

n and solutions

to problems

Future recommendation

Solar water heating system

• commercial building should 100% rely on solar energy as energy source in heating water.

• favorable to be used in Malaysia due to hot climate.

• it absorbs heat from the sun and transfer it to the water

• 2 types of solar water heating system :

a) active solar water heating system

b) passive water heating system

• 2 types of solar thermal panel

a) flat plate collector

b) evacuated tubes collector – capture sunlight better but may

overheat

Cost : flat plate collector –

US $100-500

evacuated tube collector –

US $100-250

Why choose solar thermal??Advantages

• renewable energy

• reduce electricity bill

• recommended for green building

( Green Building Index )

Disadvantages

• initial cost is relatively high

[ running cost is low , cost of conventional fuel is low or near to zero :

depends on the availability of backup units ]

• concern on availability of hot water supply at night

[ backup unit : heat up water when sunlight is insufficient and the water is

not hot enough ]

• less suitable for high rise building

[ panel can be attached to the external wall and facade ]

Additional for future recommendation

Instead of using the traditional electric based heater / boiler , a hybrid electric heat pump water heater should be recommended

• a combination of electric water heated and heat pump

• heat pump function by absorbing heat from

surrounding air and transfer it to the water in the

storage tank

• when demand is high, it will automatically switch to

electric resistance heating

SolutionsAir locks

• water could not flow out

• air release vent should be installed

Imbalance water pressure

• pipe leakage, water hammer & noise pollution may occur

• water pressure regulator should be installed

Pipe leakage

• due to corrosion ( reaction )

• make sure pipe is always filled with hot water

• use stainless steel pipe

Insufficient hot water supply

• use bigger storage tank

• ensure that there is no leakage

Backflow

• definition : unplanned reversal of flow of water

• may occur due to difference in pressure

• can be prevented by providing an air gap

• install backflow prevention devices ( vacuum breaker, double check valve

assembly & reduced pressure backflow assembly

THANK YOU!!!

hot water system presentation slide

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