Cfrgtkky

I was already helped to obtain the chapter title formatting that I wanted in Chapter with graphical formatting

Now I have the problem of chapters with a long title, whereby I get

with this code

documentclass{book} 



%PAGES

usepackage[

    vcentering, 

    hcentering, 

    inner=16mm,

    outer=16mm,

    top=22.0mm, 

    bottom=15.0mm,

    headsep=9.3mm,

    headheight=5mm,

%   showframe

    ]

    {geometry} % Extended page layout customization



geometry{papersize={189mm,246mm}} % Possible dimensions of textbook pages

%usepackage[cross,a4,center]{crop} %Package to print on A4 with crop signs. 

usepackage{multicol}% handling of multicolumn in documents

usepackage[toc]{multitoc}%enables table of contents with multiple columns

    renewcommand*{multicolumntoc}{2}% Set two columns for the table of contents

usepackage{emptypage} % suppresses page numbers and headings on empty pages

usepackage{xcolor}[2007/01/21] % Driver-independent color extensions



%SKETCHES AND PLOTS

usepackage{tikz} % To create graphics programmatically. TikZ is build on top of PGF. 

    usetikzlibrary{decorations.markings,arrows,backgrounds}

    usetikzlibrary{patterns}

    usetikzlibrary{shapes.misc, positioning}

    usetikzlibrary{calc}



usepackage{xcolor}[2007/01/21] % Driver-independent color extensions

    definecolor{BlueGreen}{RGB}{7,116,159}

    definecolor{LightBlue}{RGB}{185,229,251}

    definecolor{LightGreen}{RGB}{203,231,211}  



%FONTS

usepackage{fontspec}%LuaLaTex fonts

    setmainfont[Ligatures=TeX,ItalicFont={Apollo MT Std Italic}]{Apollo MT}

usepackage{titletoc,xpatch}%

usepackage[explicit]{titlesec}% An in­ter­face to sec­tion­ing com­mands for se­lec­tion from var­i­ous ti­tle styles.



%Font families

newfontfamilyAvenir{Avenir}

newfontfamilyAvenirLight{Avenir Light}

newfontfamilyAvenirHeavy{Avenir Heavy}





%Chapters in TOC 

newcommand{chaptertocfont}        {fontsize{10}{12}color{red}AvenirHeavy}

newcommand{chaptertocpagefont}        {fontsize{10}{12}color{red}AvenirHeavy}



%Chapters

newcommand{chapterfont}       {fontsize{24}{27}color{black}AvenirLight}

newcommand{chapternrfont}     {fontsize{24}{27}color{BlueGreen}AvenirHeavy}





titlecontents{chapter}% section-type

    [1.5em]% <- changed

    {vspace*{0.6cm}}

    {chaptertocfontcontentslabel{1.5em}}% <- changed

    {hspace*{-1.5em}}% <- changed

    {hfillchaptertocpagefontcontentspage}



%CHAPTER HEADINGS

titlespacing{chapter}{2cm}{-0.7cm}{1.7cm} % set spacing: left, before, after



titleformat{chapter}[hang]% command to be modified

    {chapterfont} %format

    {hspace*{-2.7cm}

        tikz [anchor=base, baseline,remember picture, overlay]

        {% colorbox for the chapter number

        node[

        line width = 1pt, 

        draw=BlueGreen, 

        fill =LightBlue, 

        anchor=base, 

        rectangle,  

        text width=2cm, 

        align=right, 

        rounded rectangle,

        rounded rectangle west arc=5pt, 

         minimum height=15mm,

        inner sep=11pt

        ] (A)

        {

        chapternrfontthechapter};

        draw[line width = 1pt, red] let p1=(A.south east), p2=(current page.east) in  ([xshift=2.6ex]A.south east) -- +(x2,0);

        }

    }% label

  {dimexpr2emrelax}% sep

  {#1} % before-code

   % after-code



begin{document} 



tableofcontents



chapter{Energy Conversion Systems}



chapter[Thermodynamic Properties of \ Multicomponent Fluids]{Thermodynamic Properties of \ Multicomponent Fluids}



end{document}

I tried all the examples I could find and I cannot get it to look like

How can I get the indentation, no hyphenation and the red ruler correct?

I do not have your fonts, but maybe the following helps:

documentclass{book} 

usepackage{lipsum}



usepackage[

  vcentering, 

  hcentering, 

  inner=16mm,

  outer=16mm,

  top=22.0mm, 

  bottom=15.0mm,

  headsep=9.3mm,

  headheight=5mm,

%  showframe

]{geometry} % Extended page layout customization

geometry{papersize={189mm,246mm}} % Possible dimensions of textbook pages



usepackage{fontspec}



usepackage{multicol}% handling of multicolumn in documents



usepackage{tikz} % loads also xcolor, graphicx, ...

usetikzlibrary{shapes.misc}

usetikzlibrary{calc}

definecolor{BlueGreen}{RGB}{7,116,159}

definecolor{LightBlue}{RGB}{185,229,251}

definecolor{LightGreen}{RGB}{203,231,211}



usepackage{emptypage}



usepackage{tocbasic}

addtotoclist[jobname]{toc}

renewcommand*tableofcontents{listoftoc[contentsname]{toc}}

BeforeStartingTOC[toc]{begin{multicols}{2}}

AfterStartingTOC[toc]{end{multicols}}



DeclareTOCStyleEntry[

  beforeskip=.6cm plus 1pt,

  entryformat=chaptertocfont,

  pagenumberformat=chaptertocpagefont,

  raggedentrytext=true

]{tocline}{chapter}

newcommand*{chaptertocfont}[1]{normalsizebfseriestextcolor{red}{#1}}

newcommand*{chaptertocpagefont}[1]{chaptertocfont{#1}}



usepackage[explicit]{titlesec}

titlespacing{chapter}{2cm}{-0.7cm}{1.7cm} % set spacing: left, before, after



titleformat{chapter}[hang]% command to be modified

  {chapterfont} %format

  {hspace*{-2.7cm}

    tikz [baseline,remember picture, overlay]

    {% colorbox for the chapter number

    node[

    line width = 1pt, 

    draw=BlueGreen, 

    fill =LightBlue, 

    anchor=base, 

    rectangle,  

    text width=2cm, 

    align=right, 

    rounded rectangle,

    rounded rectangle west arc=5pt, 

    minimum height=15mm,

    inner sep=11pt

    ] (A)

    {chapternrfontthechapter};

    }

  }% label

  {2em}% sep

  {%

    tikz[baseline]{%

      node[

        anchor=base,

        align=flush left,

        text height=dpstrutbox,

        text width=textwidth,

        inner xsep=0pt

      ](A){#1};

      draw[

        overlay,

        line width = 1pt,

        red

        ]

        let p1=(A.south west), p2=(current page.east) in

        ([xshift=-.6ex]p1) -- +(x2,0);

    }%

  }% before-code

  % after-code

newcommand{chapterfont}{fontsize{24}{27}selectfontcolor{black}}

newcommand{chapternrfont}{fontsize{24}{27}selectfontcolor{BlueGreen}bfseries}



begin{document} 

tableofcontents

chapter{Energy Conversion Systems}

lipsum

chapter{Thermodynamic Properties of Multicomponent Fluids}

lipsum

end{document}

Result:

If there should be no line below of the unnumbered TOC title, you have to add

titleformat{name=chapter,numberless}[hang]

  {chapterfont} %format

  {}% label

  {0pt}% sep

  {#1}% before-code

  % after-code