Appunti di Impianti dell'edificio - Building services Notes

Building Service - BOOK

Building Service

Notes based on the lessons and

materials provided by the professor

Prof. Mario Motta

2023/2024

1 Building Service - BOOK

Climate change from causes to solutions ................................................................................ 5

CHAPTER 1: ................................................................................... 5

IPCC - Intergovernmental Panel on Climate Change

.................................................................................................................................................... 6

Peer review ................................................................................................................ 6

Observed Warming and its Causes .............................................................................................................. 7

Temperature – Indirect observation .................................................................................................... 7

What we can do to limit Global warming?

............................................................................................................ 8

What does «CO2 equivalent» mean ?

Heat exchanger .......................................................................................................................... 9

CHAPTER 2: ............................................................................................ 9

General characteristics of the heat exchangers

................................................................................................................ 9

Classification of Heat Exchangers

................................................................................................................................................ 12

HX functions .................................................................................................. 12

Logarithmic mean temperature difference ................................................................................................. 15

Multipass and Crossflow Heat Exchangers ....................................................................................... 15

The ε-NTU Method for Heat Exchanger Analysis

Thermal generation in buildings based on fossil fuels ......................................................... 18

CHAPTER 3:

............................................................................................................................................................ 18

Fuels .................................................................................................................................................. 18

Combustion ........................................................................................................... 19

Complete vs. incomplete combustion

........................................................................................................................... 20

The combustion efficiency ....................................................................................................... 21

The combustion efficiency: calculation

.................................................................................................................................... 21

The boiler efficiency ........................................................................ 22

Convection and radiation losses through the boiler casing 23

Boiler losses.................................................................................................................................................

............................................................................................................................................... 23

Classification .......................................................................................................................................... 23

Hot water boiler ........................................................................................................................... 24

Types of Hot Water Boiler .................................................................................................... 24

Floor standing boilers: Fire-tube boilers ................................................................................................... 25

Actual technology: floor standing boilers

........................................................................................................................ 26

Costant T boilers (>=70°C) ............................................................................... 27

Temperature compensation boilers (low temperature)

...................................................................................................................................... 29

Condensing boilers ....................................................................................................................... 30

Heating systems components

...................................................................................................................................... 30

Distribution system .............................................................................................................................. 31

Heating systems circuits

Hydronic circuit ...................................................................................................................... 32

CHAPTER 4: ................................................................................................................................................... 32

Definitions 2 Building Service - BOOK

..................................................................................................................................... 33

The hydronic plants ..................................................................................................................... 33

The hydronic plants: hydronic

............................................................................................................................... 34

Objectives of balancing ........................................................................................................................ 34

Example of hydronic circuit

....................................................................................................................................... 34

Network extension

............................................................................................................................................. 35

Control system ...................................................................................................................... 36

Balancing of hydronic system ........................................................................................... 37

Changing of characteristic curve of the circuit

........................................................................................................................ 37

Equivalent electrical circuit

................................................................................................................................... 39

Balancing procedure .............................. 39

Regulation and balancing of system with constant flow rate at the generation system

................................................................... 39

Balancing devices: balancing valves and Autoflow regulators

Ventilation and air-based systems ......................................................................................... 40

CHAPTER 5: .......................................................................................................................... 40

Definition of air quantities .................................................................................................................. 40

Ventilation plants classification

...................................................................................................................................... 41

Natural Ventilation ................................................................... 42

Generic classification of centralized air-conditioning systems

.............................................................................................................................................. 42

All air systems ................................................................................................................. 45

Air-water systems characteristic

............................................................................................................................... 46

Air systems components

.................................................................................................................................. 46

Air outlet components .......................................................................................................... 46

Centralised vs decentralised systems ........................................................................................................ 47

How to choose the type of air system?

Solar thermal system .............................................................................................................. 49

CHAPTER 6: .................................................................................................................... 50

Distribution by Collector Type .............................................................................................................. 50

Fundamentals: the solar radiation ........................................................................................................ 51

Scattering and absorption phenomena

......................................................................................................................... 52

Solar radiation availability

................................................................................................................................ 52

Solar thermal collector .................................................................................................................... 53

Flat plate solar collector types .......................................................................................................... 53

Collector test methods and efficiency

........................................................................................................................................... 54

Efficiency curve

PV systems ............................................................................................................................... 55

CHAPTER 7: .............................................................................................................................. 55

Photovoltaic technology ........................................................................................................................ 57

Self-consumption and Tariff .................................................................................................... 58

Electrification is the way to decarbonize

............................................................................................................... 59

Gross metering and net meetering 3 Building Service - BOOK

................................................................................. 59

Energy communities and collective self-consumption

............................................................................................................................................................ 59

BESS 4 Building Service - BOOK

CHAPTER 1

Climate change from causes to

solutions

The increase of the concentration of CO2 is caused by human activities. The Main cause are the

combustion of fossil fuels and the deforestation. From “industrial revolution” human activities have

consumed ever greater quantities of fossil fuels. Global carbon dioxide (CO2) emissions from energy

combustion and industrial processes grew 0.9% or 321 Mt in 2022 to a new all-time high of 36.8 Gt.

The other perturbation of carbon cycle, i.e., deforestation and land use change, is more difficult to

quantify.

IPCC - Intergovernmental Panel on Climate Change

IPCC: Established in 1988 by the United Nations Environment Programme (UNEP) and the World

Meteorological Organization (WMO), the IPCC's mission is to provide policymakers and the global

scientific community an assessment of the available scientific literature on various aspects of climate

change. The aim is to understand better the risk of climate change caused by human activities. IPCC

does not conduct direct research or study climate science in its own research centers or laboratories.

its role is to assess the information available to provide policymakers the basis for their

Instead,

decisions. This involves gathering, comparing, and synthesizing information that has already

been published in the scientific literature. IPCC serves as a scientific support body for the United

Nations Framework Convention on Climate Change (UNFCCC) and has several responsibilities,

including the production of assessment reports, "special reports" on various topics, and overseeing

the development of greenhouse gas emission inventories that various countries must produce under

the Convention. Every 6-8 years IPCC publishes an «Assessment Report» and a «Special Report» on

request. The Sixth Assessment Report (AR6) is composed by:

3 volumes from 3 Working Groups (WG1 - The physical science basis. WG2 – Impacts,

• adaptation and vulnerability. WG3 - Mitigation of climate change), full of information and

details(~1000 pages each volume)

1 Technical Summary (~100 pages) and 1 Summary for Policymakers (SPM) for each

• working group (30-40 pages)

Each finding is grounded in an evaluation of underlying evidence and agreement. The IPCC calibrated

language uses five qualifiers to express a level of confidence: very low, low, medium, high and very

high, and typeset in italics, for example, medium confidence. The following terms are used to indicate

the assessed likelihood of an outcome or a result: virtually certain 99–100% probability, very likely

90–100%, likely 66–100%, more likely than not >50–100%, about as likely as not 33–66%, unlikely

0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%. Additional terms (extremely likely 95–

100%; and extremely unlikely 0–5%) are also used when appropriate.

The most distinguished and complete source for climate change impacts is the second volume of

IPCC reports. The reports of IPCC-WG2 carry out a detailed assessment of different types of climate

change impacts, with a global and continent-wide assessment of key risks, adaptation measures and

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their potential to reduce risks over different time horizons. IPCC-WG1 has summarized the

projections of estimated temperature levels from scientific literature, through climate models, for

different GHG emissions scenarios. Then, IPCC-WG2 has described the expected impacts for

different temperature levels. “Risks and projected adverse impacts and related losses and damages

from climate change escalate with every increment of global warming (very high confidence).” For

every level of future warming, many climat-related risks are higher in AR6 than those evaluated in

AR5. At Italian level, the most distinguished and complete source are the preparatory studies for the

National Plan for Adaptation to Climate Change - Piano Nazionale di Adattamento ai Cambiamenti

Climatici (PNACC), particularly Annex III - Impatti e vulnerabilità settoriali (375 pages).

Peer review

It is a fundamental process for the dissemination of scientific knowledge. The more rigorous the

review process is, the more serious the journal is. It is not an infallible process, but it allows for a

great screening. Many Italian journals do not have peer review systems, while others have a very

mild review process. For conference proceedings and seminars, the review is minimal. Many reports

from private organizations do not have peer review systems. In addition to rely almost entirely on

articles published in journals with peer review systems, IPCC carries out a double peer review cycle.

Reviewers are researchers who volunteer by submitting their own CVs.

Observed Warming and its Causes

Human activities, principally through emissions of greenhouse gases, have unequivocally caused

global warming, with global surface temperature reaching 1.1°C above 1850-1900 in 2011-2020, 1.1

°C is the so called global temperature anomaly. The term temperature anomaly means a departure

from a reference value or long-term average. A positive anomaly indicates that the observed

temperature was warmer than the reference value, while a negative anomaly indicates that the

observed temperature was cooler than the reference value. Global greenhouse gas emissions have

continued to increase, with unequal historical and ongoing contributions arising from unsustainable

energy use, land use and land-use change, lifestyles and patterns of consumption and production

across regions, between and within countries, and among individuals (high confidence). Average

annual GHG emissions during 2010–2019 were higher than in any previous decade on record, while

the rate of growth between 2010 and 2019 (1.3% yr-1) was lower than that between 2000 and 2009

(2.1% yr-1). In the Earth’s atmosphere the greenhouse gases (CO2, methane and others) traps heat.

The temperature increase in the last century is unprecedented over at least the last 2000 years, Global

surface temperature has increased faster since 1970 than in any other 50-year period over at least the

last 2000 years (high confidence). Temperatures during the most recent decade (2011–2020) exceed

those of the most recent multi-century warm period, around 6500 years ago [0.2°C to 1°C relative to

1850–1900] (medium confidence). Widespread and rapid changes in the atmosphere, ocean,

cryosphere and biosphere have occurred. Human-caused climate change is already affecting many

weather and climate extremes in every region across the globe. In fact in different areas of the planet,

the extreme events frequency of temperature and precipitation is increased, for Extreme events is

intended events that are placed in the extremes of the distribution of the «historical» frequencies, with

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which the events are occurred in the past. So, the temperature change leads not only to a change in

average values but also to a greater probability of occurrence of extreme values. This has led to

widespread adverse impacts and related losses and damages to nature and people (high confidence).

Vulnerable communities who ha